i have one. it does a fine job. sounds as good as or better than the pres on my mackie 24*4 (depends on my ears, the mic, the source, planetary alignment, warp core breaches, etc.). i like it better for lead vocals than the mackie, for sure.
haven't tried it against anything "better" or more expensive, so i can't help you there. the dmp3 would be a better "deal" as it's stereo where the vtb1 is mono, and the dmp3 is highly regarded around here, but i don't have one to compare against.
i mean, it's only $125 these days and has sounded usable with the small handful of mics i've thrown its way (B1, sm58, shure unidyne 545,
senn e835), and i'm looking forward to giving my newly arrived RE-38 a go with it tomorrow or friday....so i really can't complain.
i've found it to be a really nice DI for my tele with the neck pickup and the toob slightly engaged (10-2 seems to be the "usable spot")--nice and bluesy, and far thicker than i'd expected it to be. with the toob fully driven and playing through the humbucker i installed in the bridge (Seymour Duncan Little 59 for tele), it sounded thin and anemic and far too crackly (rather than deep and ballsy). in other words, pretty much what i expected it to. haven't tried it on bass, but to be honest, i'm not expecting much there.
bottom line, would i buy another one if this one got stolen? maybe. would i buy a second so i had a pair? not likely. would i sell this one? prolly not. will i still pick up a dmp3 at some point? you bet.
the vtb1 is simply a usable preamp and can give you a couple interesting sounds. i think this pre was made with the B1 in mind (or vice versa), and does a nice job bringing out detail in a shure unidyne 545--switching the impedence to 50 ohms was the trick there. it's really nothing to write home about (although as mentioned, the DI had a shocking benefit and i'd keep it around for that, if nothing else).
given the choice to do it over, i'd prolly buy the dmp3 simply b/c it's 2 channels instead of one. but i'm sure the vtb1 has a far different sound, as well. and the blue looks cool glowing in a dark room.
i don't think you'd be doing yourself a disservice by checking one out if you get the chance.
wade