Couldn't find anywhere that says it uses USB 2. Because of that, I won't be surprised to find out that it doesn't. That'll make a BIG difference in bandwith.
No S/PDIF out?! WTF? Even the cheapest 'prosumer' sound cards usually have an imput for it. Balanced outputs is OK... but it seems like Digitech is pushing this unit primarily for use with a DAW. (Included software, USB, etc...) Having no S/PDIF is kinda lame.
If it's like most of the similar Digitech stuff that's been coming out over the last year or so, it's mounted in/on a plastic case that I don't find too appealing. Not built to last. (or used for stage, for that matter, which even more so supports my "primarily for use with a DAW" comment.) I mean, cummon... you ARE gonna be STEPPING on this thing!
Also, the amp and analog processor sections of Digitech units, have frequently been known to be notoriously noisy. The digital processing can be incredibly quite, considering the price.
Compared to other devices that will do all or some of the same as this unit, you'll be lucky to end up getting what you paid for. $300 is pretty damn 'cheap' after all.
I would be sure to check out what 'Boss' / 'Roland' has to offer, that's similar, and be willing to pay more for it, instead. Probably won't have to pay all that much more, either.