I've heard the 6300 and 6600 and was disappointed. The 6300 struggled to drive an ATC SCM11 which to some degree is understood. The 6600(200w/ch) sounded anemic mated to a Sonus Faber Liuto. Was it synergy or the MAC cd player? These are only 2 examples but they do raise caution. You might want to demo the MA7000 which has the autoformer design. With the lower priced MAC gear your buying the name and resale value NOT sound quality as the first priority.