I have extensively used the TwinTrak Pro and the VoiceMaster Pro. I have been able to get very good sounds out of both units for many different applications. However, I will admit there are a few controls on each that are pretty worthless in the sense that you might get lucky turning knobs and get a good sound for one thing, but using your brain to make an educated guess will often yield poor results. Sucks, I know.
Anyway, here's my breakdown.
VoiceMaster Pro
first thing I say is I love the ability to on/off each section of the channel strip for a/b comparisons. REALLY helps.
Front side 1/4" and XLR inputs were very convenient for so many things I used it for. Of course, it's got them in the rear also. Ouch!!!
Decent quality Class-A Preamp... not necessarily a great pre-amp for the price range, but considering the unit's other goodies, it's still a decent sound.
Sweepable Low Cut filter (which I loved, and used almost every time)
Compressor is very average and you're better off with a different unit here. Even a low budget like a DBX 266 or 166. Don't like the metering, as it isn't detailed enough for fine adjustments of around a db or two.
Vintage Harmonics and Tube Sound can give some truly Terrific and unique sounds, but this is more of a turn the knob til it sounds good type of feature, and if it still sounds bad, turn it back off. Kinda lame I know.
The De-Esser is pretty nice, it is identical to some very expensive units like the ISA 430, but I can get pretty similar results from the de-esser built into Logic Pro for free.
EQ section is pretty useful, if you're recording live to tape or something to that effect, but I am much more a fan of EQing in the mix, and forcing the EQ to be close as recorded.
Overall, good for vocals as I'm sure you'd imagine. The upper-mids are very clear with this setup, and you can get just a little bit of clean grit out of it for a sound that can really cut through the mix. Also sounds really damn good as a Bass DI in some applications.
TwinTrak Pro
Pretty decent unit for the money, but there's not a single thing it does better than factory logic plugins imho. Granted, I've gotten some really good stereo recordings out of this thing for
Yamaha C5 piano, acoustic guitars, and even drum Overheads. Like the sidechaining for the comp, but not sure if the single channel version has this??? anybody?