I have never owned the others you mention, but listened to the Aragon and the Sunfire. I purchased the Sunfire Cinema Grand Signature as I prefered its power AND nuance over the Aragon. I needed an amp that would allow me to drive a very difficult load (Magnegan MGIIIA) for 2 channel listening, as well as in 5 channel mode for film. I have lived with it for almost a year now and am very happy with it. It has slam, nuance, power to spare, great dynamic swing, AND it runs very cool unless being driven to unspeakable dbs. I have most of my gear, including the amp, located in a closet outside the room, and I did not want the amp working as a space heater cooking the processor, preamp, SACD player, and CD player. The Aragon, IMHO, was a very sweet sounding amp, but when asked to drive 4 Magnepan speakers for film, I was a little concerned about it running out of headroom. If you are going to use fairly efficient speaker systems, look at both, and let YOUR ears tell you what to do. I have never listened to the Adcom multichannel product, but I did own a 535 2 channel amp in the late 80's to drive a pair of Magnepan SMGa. I loved that amp. I think it may be one of the best, if not the best amp Adcom ever built.
