Arcam AVR-300 vs. B & K AVR 507 vs. Rotel RSX-1067

For use in 2400 cubic foot room (15 x 20 x 8) with Magnepans.
AVR507 is much better IMO than the other 2. Very powerful, non-current limiting amps, and great build quality. The pre sections of all 3 are very good, it's the amps that make the difference - especially when driving low efficiency speakers.
Those speakers are power hungry, get seperates, plus seperates will sound better than any reciever. I almost bought that same Rotel, I bought a Rotel processor new, and used amps from AGON and never looked back. You have too good of a speaker for an all in one box reciever.
i have used a b&k 307 receiver with aerial 10t main speakers for a while. i believe my sound improved when i put a sherbourn amp in the system. the 10 t's just like a lot of power and it is well known they sound better the more you give them. it led to better bass control and a bit more neutral sound, the b&k leaned towards warmth. i think your speakers have the same characteristics. i am now looking for a seperate processor and a seperate 2 channel preamp to complete my system. i did not audition the other units you are considering, but i would also look for seperates and as many clean watts per channel as you can get.
Steve, if you've got smallish Maggies the AVR300 will drive them just fine and IMO has a much better linestage/pre-pro than the B&K, which would be my second choice. Your room is not that big. (I've got a 19x40x8.5 room). The AVR300 sounds much more powerful driving my Alons than its specs might suggest. (I had Maggies for years, BTW.)

If you also plan to do music listening on this rig the AVR300 is the one to get. Dump the stock cord and get a good after market PC and you'll be set.

If you have Maggie 1.6s or larger you'll ultimately need separates with high current amps.
If you care enough about sound to get Maggies, you might want to put serious thought into seperatesk, you can get so many deals on slightly used amps or pre's or processors the choice is so limitless..try seperates!
I , too would like to know who has actually listened to both of these recievers. I own a 507 with an Arcam DVD player and Monitor Audio Speakers. Though my B&K seems in great company and is making great music with its fellow Brits, I have to wonder how the Arcam reciever would sound. Less power, yes, but my newest addition was the arcam dvd player and it just simply is the best dvd player I have heard other than the 5k esoteric....I know the reviever has to be good...BUT the B&K is great as well...
"Though my B&K seems in great company and is making great music with its fellow Brits, I have to wonder how the Arcam reciever would sound."

A minor point, but B&K is a US and not British company.