You will notice a immediate improvement interms of resolution & bass control.. & the decay of instruments.. More people need to buy this amp.. I guess 550 makes them un FOTM friendly, & people don't see them as a good bang for the buck.. I guess an amp must be 400 or less to make that list..Sad.. The GP amp is clearly on par with sub 1,000 amps.. That alone makes it a great BFTB..
As for higher resolution. Is the treble more extended?
Soundstage any difference?
bass more controlled... Bass do get tighter not just more of it?
Overall balance is it pretty much the same or did it go brighter/darker?