The F1 is also my favorite amp, maybe of all time at this point.
However, just to clarify my comments on the 502 (and hence my Epi Micro amp expectations), I really do have a love/hate relationship with that amp. It sounds SO good solo... fat, big down low, HUGE headroom, a very 'woody' organic mid response, and a very clean, crisp hi fi top end. It really is a very 'studio board' type sound, and I actually keep it set up at home to practice and noodle with.
However, given the big low end and the somewhat limited EQ (lot's of bells and whistles, but still basically bass, mid treble), I've had BIG trouble with this head in boomy rooms.
The F1, while sounding a bit 'rougher' in the mids and 'thinner' down low solo, just seems voiced wonderfully for live performance. It seems to be voiced to just sit right where a bass guitar should sit in a live pop/funk sort of mix.
Anyway, I think my earlier post came out more negative than I meant. For certain playing contexts, the Epi amps are really beautiful. However, similar to my experience with the Glockenklang Heart Rock, that big low end, very pristine, pretty high end, and smooth mids can be very addictive solo, and can also be very frustrating in a less than perfect live situation.
IMO!
K