As I was saying in your other thread, I know someone who used to own all Sunfire AVP and amps. Now he changed to Marantz AVP + ATI amps + RBH SVTR speakers.
For amps, there are so many options (ATI, Parasound, Rotel, Anthem, Bryston, Legacy, etc.). Other than price, I think the 2nd biggest difference will be warranty and customer support. Company reputation and pride of ownership is also a factor for many people.
In terms of sound quality, all of them will sound great depending on your setup.