I've been digging on my THD univalve lately. on it's own it's just a decent sounding amp. but when recorded it is so alive. It also stacks better than any amp I've ever used. I've been a card carrying Harlequin user for a while (and still am) but there is just something about the character of the univalve that is unique to me. . .
as far as just listening to an amp - I played a vibroking once and I was flawed by the tone. soooo smooth and buttery (a sound I've been searching for a long time) - I almost paid an extra hour at the rehearsal space to futz w/ it . . . but then I would have had to leave w/ it