Hi Beatlebum
I just purchased the ARC 150.2 amp, last week. Needless to say my experience as yet is very limited; however for what it's worth here goes.
I upgraded from the ARC D-130 and my first shock was when I went to pick up the new amp, this thing is twice the size and weight of the D-130. While I really haven't had it long enough to even get it broken in as yet, several things are obvious: 1) the base is much more prevalent than the D-130, 2) while I don't listen at real high volumn levels, one can sense that there is much more power here, and 3) the inner detail and definition are outstanding.
In reference to this last point I always play the 'te deam' by Hector Berlioz (to test new equipment) as it has a large organ, full concert orchestra and a hugh choir w/soloist, so it gives you the full spectrum. The inter detail with the voices were cleaner and clearer than I have ever heard them, it was as if you could hear each indiviual voice. The tonal timbras are all very close to natural, and it just seems to give a very natural musical picture.
I am told, that it really takes several months to be at its best, however obviously I cannot attest to this.
To answer your question, to this point I am very happy with it's performance with no reservations.
Good luck, I think you will like it.
Regards,
AEW