Yes USB audio devices use drivers, but DACs do not require additional drivers which sound cards do. Sound card drivers are usually fine until the support stops. A DAC will never have that problem.
I think the chances of having software issues with a USB DAC are much less than a sound card, purely because there are no additional drivers to install.
However; I wouldn't put it past Microsoft to break all audio, whatever it is....
Reading some of the other threads on here and elsewhere it sounds like for around a £100 a pair of AKG K702 headphones might be a nice upgrade? Open backs would be pretty useful for using at home so I can still hear a bit of what's going on when I'm gaming. I understand something like the Creative E5 are a good option to get away from the onboard audio, but not sure if I want to be relying on something with drivers again, so maybe still the Fulla 2?
AKG K702 are great for gaming and one of the best for positional sound location if used with SBX prostudio found on Creative sound cards.
I suppose it depends whether locating sounds from other players in FPS type games is something you'd really want. I've had it on a few sound cards I've had from Creative and Asus, but I don't use it now and I don't miss it at all; but then, like yourself, I don't play much in the way of FPS games and when I do, never competitively.
I've seen posts from various people when it comes to positional sound location in games; some want it, some aren't fussed and some think it just sounds bad. For those who could take it or leave it, maybe competitive is a key word when it comes whether positional sound is of real benefit or not. For those who play competitively, it's a must really, as it can be a real advantage when done well. For those who aren't bothered about playing competitively, maybe positional sound location is not really important. Of course though, it doesn't work for everyone, hence those who think it just sounds bad.
Esat seems to think it's a must have for anyone who plays a game and he can't seem to understand that some people don't want it or like it.
I suppose though, you can't know if it's something you'd miss if you've never experience it properly. The video that Esat linked would be a good way to get some idea of whether it would be something you are interested in.
If not, and you have no need for microphone input, a Fulla 2 or E10K are good options. That's one thing that hasn't been made clear yet; DACs are audio out only, no microphone input.
If positional sound location from a Creative Soundblaster E5 or similar is something you'd like, and it's the thought of bad drivers that is the only thing putting you off by getting a sound card, then Creative have been pretty good of late with their driver support. For a USB sound card, I'd take Creative over Asus any day. Asus driver support really is abysmal, and for their USB sound cards, there are no alternative modified drivers like there are for the internal Asus sound cards.
Seems to be swings and roundabouts though when it comes to sound card support. When Vista came out, Creative were abysmal. Asus did well at that period; now Asus are abysmal and Creative are doing well. Who knows if or when Creative will go back to being abysmal. For me, Bledd and some other's, having a sound card for positional sound location, is not important enough to have that it would be worth the bother should sound card driver support could go south, whether it be Creative or Asus. For those that really want what SBX prostudio provides, and get real benefit from it, it's most likely worth it even if there is a possibility that driver support could go south at any time.