The GFA 5802 is a highly regarded Adcom amp. I owned one at one point (prior to my Thiels though), and it drove a pair of Aerial Acoustic 10T’s nicely. However, I understood that it would be very difficult to repair if any issues arose with the output hexfets (NLA?). I ended up selling mine partially because of this concern, but I don't know how valid of a concern it was.
FWIW, I am running Levinson 436’s (CS5) and Aragon Palladiums (CS7.2) currently. I have thought about buying one of the big Krells to compare, but haven’t pulled the trigger.