Yeah, pretty much the same. Not really alot of difference between the 2. But from what I've been able to discover, some claim the G930 is a little lighter in weight than the G35 (surprisingly) but the difference is negligible. I've had no problems with the drivers yet (touch wood) and they've been the best I've used that have good game sound, positional audio, and music reproduction. I bought the sennheiser pc350's thinking they would be good for both, and although the game sounds were first rate, I was terribly dissapointed in the music reproduction (which surprised the heck out of me, considering sennheisers' rep with music reproduction)
As for the Corsair Vengeance 2000, I am unfamiliar with them, but a quick look over their specs show that they're not too different, similar range, battery life, etc. However, that said, there can be a huge difference between how headsets are spec'd and user satisfaction. My best advice is to call in to your local shop and try them out. The G930s' aren't for everyone, some people hate them, others love them. After my experience with the pc350's I will never buy a headset that I cannot try out in store.
Hope this helps, good luck.