I agree with Rsjm80 that the OP is pitting 2 strong contenders against each other.
The B&W Matrix was designed when John Bowers himself was alive back in the early 1990s (maybe even the late 1980s). I've not heard the Matrix 801S2 but I did hear a smaller Matrix speaker (I *think* it was the 803) with Threshold & McIntosh electronics at Audio Consultants in the Chicago area. I really liked the sonics but it was unaffordable at that time for me. I have also heard the N801 overseas at a dealer driven by Rowland Model 10 amps. Altho' the room was large enough to accommodate the large woofer of the N801, I did not like the sonics - too tipped up towards the mids & highs & plenty of bass overhang.
I have a friend who lives in Paris, FR who owned & still owns a pair of B&W Matrix 801 & really liked the sonics but he got 'upgraditis' when B&W introduced their N8XXD series (not this very latest series but the one just before). So, he called B&W in England & managed to snag a used pair of N800D from the manuf that they/B&W used in their listening room on-premises. He got a great deal on them price-wise & was really excited to get the latest & greatest from B&W. He drove from Paris to the manuf & picked them in person. After several months of listening, when I communicated with him, he told me that his Matrix 801 speakers were simply much better than his new N800D speakers. He told me that the new N800D had many of the audiophile attributes but it had no soul. Where the N800D made great sounds, the Matrix 801 made music. He had both speakers in his room & did many A/Bs in his setup. Soon afterwards, he sold off the N800D. The Matrix 801 are still in his listening room.
If the OP doesn't already know it, then several of the B&W fans over here can chime in - the Matrix series speakers from B&W were some of their very best sounding. The Matrix series speakers is what put B&W on the map & of course, it's use in Skywalker Labs in the UK. It's hard (but possible) to destroy the cone drivers esp. with the use of high order x-over like B&W likes to use.
Compared to B&W's present-day offerings, the Matrix speakers were easier to drive as can be seen in this measurement done by Stereophile http://www.stereophile.com/content/bw-matrix-801-series-2-loudspeaker-measurements
looking at the impedance & phase curves at, say, 200Hz, I see 12 Ohms & 22.5 degrees of phase shift. That translates to 11.1 Ohms real part (ie. resistance) & 173uF (imaginary part). The imaginary part is reactive power where the current in the capacitor is 90 degree ahead/phase lead compared to the voltage. I see that between 40-50 degrees the phase shift goes inductive (where the current will be behind/phase lag compared to the voltage). So, in the 20-200Hz region I see phase-lead & phase-lag meaning that the amp will have a relatively tough job as it tries to maintain the voltage-current relationships. But, you'll notice that the resistance values are pretty high - 11.1 Ohms in the above calc & 9 Ohms (minus a little due to phase lead). Driving current into these fairly high resistive values in the bass region (many of today's speakers go down to 4 Ohms or lower) means that the Matrix 801S2 is an easier load than B&W's today's offerings & by a long shot.
The Matrix 801S2 speaker is really very good sonically provided you have the room for such a large speaker & can give the 12" woofer the space it needs to go down to 20Hz (as the spec says). This is a very large room or a very well acoustically treated room.
I agree with Rsjm80 again that the it's very hard to beat the sonic attributes of a ribbon. Physics will always be on the side of the ribbons due to their lighter weight. I got a low-down from the seller from whom I bought my Apogees from. Over his music listening years he had owned 8-9 different Apogees including the Centaur Major. His present speakers are the Apogee Full Range & at that time his 2nd bedroom system had the Apogee Slant6. From the info he gave me I learnt that of all the hybrid speakers Apogee made the Centaur Major was their best. The integration of the cone woofer with the ribbons was done very well to where most of the time this person could not tell when the sound transferred over to the bass driver & back to the ribbon. Yes, the unfortunate thing about Apogee is that they are not in business today so if the ribbon needs replacement you are likely to badly off. I did find a seller in Singapore selling ribbons for various Apogee models but you might think 'who wants to deal with that' & maybe rightly so. The seller I was in touch with ranked the Apogee Stage as having the best mids & highs (of course within the Apogee offerings) which he ranked at 100, 2nd came the Centaur Major, which he ranked at 99 & 3nd came the Scintilla (these were the ones he was selling me) which he ranked at 97. So, all very close but he had finite ranking for them based on his extensive ownership & listening of these speakers. You can read a review of the Centaur Majors here: http://www.apogeespeakers.com/reviews/Centaur_Major_Stereophile.pdf
So, like Rsjm80 states, you can't go wrong with either speaker - both are really very, very good even today. From my personal experience the B&W Matrix series beats B&W's present day offerings any day - more soul, more music, more looking into the music & less audiophile attributes.
The Centaur Majors have hallmarks of a very good ribbon (that I heard in the Maggie 1.6, Soundlab U-1 at RMAF 2007, my own Scintillas, Selah Audio speakers based on Newform Research's ribbons). The mids & highs are very natural. You might want to check the conditions of the ribbons thoroughly before you buy. My Scintillas have original ribbons from the 1985 build so no reason why original ribbons cannot last long. If the prev owner has abused them then that's another matter.
Maybe the availability of replacement drivers will make up your mind??
The B&W Matrix was designed when John Bowers himself was alive back in the early 1990s (maybe even the late 1980s). I've not heard the Matrix 801S2 but I did hear a smaller Matrix speaker (I *think* it was the 803) with Threshold & McIntosh electronics at Audio Consultants in the Chicago area. I really liked the sonics but it was unaffordable at that time for me. I have also heard the N801 overseas at a dealer driven by Rowland Model 10 amps. Altho' the room was large enough to accommodate the large woofer of the N801, I did not like the sonics - too tipped up towards the mids & highs & plenty of bass overhang.
I have a friend who lives in Paris, FR who owned & still owns a pair of B&W Matrix 801 & really liked the sonics but he got 'upgraditis' when B&W introduced their N8XXD series (not this very latest series but the one just before). So, he called B&W in England & managed to snag a used pair of N800D from the manuf that they/B&W used in their listening room on-premises. He got a great deal on them price-wise & was really excited to get the latest & greatest from B&W. He drove from Paris to the manuf & picked them in person. After several months of listening, when I communicated with him, he told me that his Matrix 801 speakers were simply much better than his new N800D speakers. He told me that the new N800D had many of the audiophile attributes but it had no soul. Where the N800D made great sounds, the Matrix 801 made music. He had both speakers in his room & did many A/Bs in his setup. Soon afterwards, he sold off the N800D. The Matrix 801 are still in his listening room.
If the OP doesn't already know it, then several of the B&W fans over here can chime in - the Matrix series speakers from B&W were some of their very best sounding. The Matrix series speakers is what put B&W on the map & of course, it's use in Skywalker Labs in the UK. It's hard (but possible) to destroy the cone drivers esp. with the use of high order x-over like B&W likes to use.
Compared to B&W's present-day offerings, the Matrix speakers were easier to drive as can be seen in this measurement done by Stereophile http://www.stereophile.com/content/bw-matrix-801-series-2-loudspeaker-measurements
looking at the impedance & phase curves at, say, 200Hz, I see 12 Ohms & 22.5 degrees of phase shift. That translates to 11.1 Ohms real part (ie. resistance) & 173uF (imaginary part). The imaginary part is reactive power where the current in the capacitor is 90 degree ahead/phase lead compared to the voltage. I see that between 40-50 degrees the phase shift goes inductive (where the current will be behind/phase lag compared to the voltage). So, in the 20-200Hz region I see phase-lead & phase-lag meaning that the amp will have a relatively tough job as it tries to maintain the voltage-current relationships. But, you'll notice that the resistance values are pretty high - 11.1 Ohms in the above calc & 9 Ohms (minus a little due to phase lead). Driving current into these fairly high resistive values in the bass region (many of today's speakers go down to 4 Ohms or lower) means that the Matrix 801S2 is an easier load than B&W's today's offerings & by a long shot.
The Matrix 801S2 speaker is really very good sonically provided you have the room for such a large speaker & can give the 12" woofer the space it needs to go down to 20Hz (as the spec says). This is a very large room or a very well acoustically treated room.
I agree with Rsjm80 again that the it's very hard to beat the sonic attributes of a ribbon. Physics will always be on the side of the ribbons due to their lighter weight. I got a low-down from the seller from whom I bought my Apogees from. Over his music listening years he had owned 8-9 different Apogees including the Centaur Major. His present speakers are the Apogee Full Range & at that time his 2nd bedroom system had the Apogee Slant6. From the info he gave me I learnt that of all the hybrid speakers Apogee made the Centaur Major was their best. The integration of the cone woofer with the ribbons was done very well to where most of the time this person could not tell when the sound transferred over to the bass driver & back to the ribbon. Yes, the unfortunate thing about Apogee is that they are not in business today so if the ribbon needs replacement you are likely to badly off. I did find a seller in Singapore selling ribbons for various Apogee models but you might think 'who wants to deal with that' & maybe rightly so. The seller I was in touch with ranked the Apogee Stage as having the best mids & highs (of course within the Apogee offerings) which he ranked at 100, 2nd came the Centaur Major, which he ranked at 99 & 3nd came the Scintilla (these were the ones he was selling me) which he ranked at 97. So, all very close but he had finite ranking for them based on his extensive ownership & listening of these speakers. You can read a review of the Centaur Majors here: http://www.apogeespeakers.com/reviews/Centaur_Major_Stereophile.pdf
So, like Rsjm80 states, you can't go wrong with either speaker - both are really very, very good even today. From my personal experience the B&W Matrix series beats B&W's present day offerings any day - more soul, more music, more looking into the music & less audiophile attributes.
The Centaur Majors have hallmarks of a very good ribbon (that I heard in the Maggie 1.6, Soundlab U-1 at RMAF 2007, my own Scintillas, Selah Audio speakers based on Newform Research's ribbons). The mids & highs are very natural. You might want to check the conditions of the ribbons thoroughly before you buy. My Scintillas have original ribbons from the 1985 build so no reason why original ribbons cannot last long. If the prev owner has abused them then that's another matter.
Maybe the availability of replacement drivers will make up your mind??