Adcom GFA 555 II too harsh for EPOS M12.2's?

Thanks for your help. I understand the Adcom GFA 555 II is a good amp w/ tons of reserve power. However, some reviews call it a little grainy, harsh and brittle. Along w/ the EPOS M12.2's I am running an Adcom Preamp/tuner and a 12" Velodyne sub. Also, my 16 x 12 room does not have carpeting, already lending to strong mids and highs. Will this amp work in my situation or do you have another suggestion in the used $400 - $500 range??
Thanks.