Keep in mind the need for power. Your room size and it's absorbtion, tastes in music, and listening levels are some considerations. I often play my Eidelons loud, and although my room is of medium size, sometimes I crave more power. I run the Eidelons with Atma-Sphere MA-2s, rated at 220 watts/ch.
Prior to the A-S amps I satisfyingly used CAT mono-blocks. At 100 wpc, only the most demanding recordings presented a power issue. I have not heard the Stereo CAT, but Ken Stevens, the designer, has proclaimed it better than the monos at half the price.
I heard the ARC amp at an audio shop, with much disappointment. Could have been the set-up, cabling, who knows... but it exposed a hard edge that the Eidelons have with certain solid state amps.
Paradoxically, I did try out a pair of Krell monos with the CAST preamp. This was a short three day audition, and, although I hate to admit it, the Avalons were very musical with nice frequency extension.
Other experiential set-ups included Classe 301 and Lamm 2.1. Both worked well, but if you can find the room, the Atma-Spheres, with the OTL design, has played the Eidelons most musically and with least want.
One last thought. I did run Avalon Ascents with Jadis JA-200s. Also, very musical, but not a great pop/rock combo. And again, these are mono-blocks.
