This was posted almost a year ago on AVS Forum. It seems to have some interesting info since the speakers were in direct comparison.
"I must say the the new Wilson WP7 is likely the best WP ever...I was always partial to the WPIII. And under the pretenses of the new found excellence of the WP7 I was given a unique opportunity to teach a local dealer a lesson about doing their homework.
In a specially treated room and the Wilson's with home field advantage ( they were setup in ther dedicated dealer approved places). The ATC SCM150's simply were wedged in between the 7's without a great deal of care.
We used a BAT VK-51 and a Krell stereo amplifer (voiding the warranty) on the Wilsons with the seemingly excellent Esoteric Universal player as a source.
The Wilson's are very good speakers they have a sense of clarity that the Aerial 20's couldn't rival and their bass extension is very commendable. Listening to a few varied cuts on the Wilsons was for the most part very enjoyable. The only complaint that I have about the Wilsons is a little bit of glare in the highs (could be electronics). The WP7's are smaller in size than the ATC 150's but I believe they required the large room we were in more than the 150's did.
The Wilson's threw a very large soundstage and created a sense of depth in the soundfield that was accentuated a little more than it really should be. Timbre's seemed to be real and the dealer/sales person was enamored with the WP sense of pace and timing. Had the SCM150's not been there and I was forced to compare these attributes with the other speaker lines sold there...I couldn't agree more.
Lest we forget that I brought SCM-150's to the party, which simply went about unravelling and exposing every single defect in the sound of the Wilson WP7. First the bass, the Watt puppy can plunder the depths but only with its own ham fisted coloration. The WP thundered on bass notes that the ATC's exposed the drum head timbres and revealed the material of the kick tom. This was a very striking difference in presentation. A difference that was actually to the Wilsons favor on a particular organ peice, but when track after track revealed the Wilson inability to play the bass that was unique to each recording it became tiresome and obvious.
Probably the most striking attribute the ATC has for this comparison is the incredible integration of all three drivers. On a particularly non audiophile track of Rick James "Superfreak" the ATC presented this pop cut with greater detail and listenability than the wilsons. If you judged the WP7 as a reference this cut seemed aggressive and lacking in all areas desirable for a listenable cut. The ATC made the Wilson presentation sound as if the music was seperated in three distinct bands of sound, bass, mids, high. they were not integrated very well making this cut nearly unlistenable on the Wilson system. Fine you say its a bad recording, well not all of it is and the ATC's proved this out by literally exposing the construction of the mix as choruses faded in and out and fills were added to build the track up the ATC's exposed these edits but never made the track unmusical, and my partners and myself felt there was no limit to how loud we wanted to listen to this fun song on the ATC's. What was striking was that some of this track is very rich and full and then other fills are aggressive and forward, it was a very interesting track on the ATC's.
Loudness is another quick note, the ATC's have probably a magnitude of 2-3 times less distortion than the WP7's, The ATC's never seemed as loud as the 7's but when turned up to compensate never became compressed when they were asked to play louder and louder. I wish I had measurements to back this comment up, but Soundstage has not reviewed a large ATC speaker system.
I would like to say that comparison was between two very good loudspeakers but once the price is factored in, the value meter drops quite a bit on the passive Wilson speakers. They were no match atleast the day I was there for the ATC system. I'm not sure juggling electronics could make up the gap, because the ATC's were also plagued by the BAT VK51se IMO. Also the ATC's were never moved about the room for best placement so there was likely more performance to be had from both speakers.
I enterred with a small amount of doubt that the ATC's would not clearly best the Watt Puppy's, especially since I hadn't heard the 7's. But there is no doubt in my mind if you would like to find value at this price point in the market, the ATC's are clear champions.
So my point is make sure ATC is on your list, there is a good reason every Telarc and Sony SACD is mastered on them."
written by "Audio Facist" 2-2-04
Hope that is helpful.