I have the 3.7 speakers. This past summer
I introduced two AHB2 amps to replace my Classe ca 300 which was having problems. They sounded so good I moved to an all Benchmark system soon thereafter: DAC 3B (replaced a Berkeley Alpha DAC Series 2, smoked it), LA4 pre and AHB2 with all Benchmark cabling.
I ran the two AHB2s in bridged mode at first, then tried just one amp. I have to say, the single amp sounds better -- better harmonic purity, focus and all the volume I need for massive orchestral music in my 19 x 20 room. I've had it as loud as anyone would want, and no clipping.
So that's my system: Thiel 3.7 and all Benchmark along with an Aurender N10 server. It sounds _fabulous_ . I've had a life as a professional classical musician with constant interaction with venues and ensembles large and small. The Benchmark AHB2 has an extraordinary purity and depth, no coloration, just the music, with instruments placed perfectly in the stage. No problem hearing into dense tone clusters in, say, Messiaen's orchestral music. Dynamics, transients, timbre is just as it should be, or rather, as it is. I feel at this point that that's it, no need to look further.