Hi,
Atg the first taas meet, our fearless leader brought along his mono extremes, and someone else brought along a Bryston 9b
(Apologies Yorgi) The extremes were in a class by themselves. Very very nice. Less dynamic and less deep bass (To my ears) but a far far nicer midrange and top end, coupled with what was really a nicely integrated bass. Very balanced presentation, great soundstage. These were among the nicest solid state amps I have ever heard, though it must be said I have never heard the big dollar sim amps, or anything by nelson pass.
The other nice solid state amps I've heard, for reference, were the classe dr2 and cam 400 (I think), an expensive new system by exposure, and, for less money, the bryston b60 (I highly preferred that to the 9b) and the monarchy sm70.
I should say that I am an avowed tube guy, and love an organic, breathy presentation. The mono extremes were the 2nd most tube like solid state amps I have ever heard, after the exposure.
hope that helps- In my opinion, you can't go wrong.