For hard core gamers it improves UDP packet transmission, bypasses the Windows network stack, and prioritizes gaming connections ahead of other stuff, average guys like me would not notice much difference, but if you are primarily a gamer you would notice some, although exactly how much would depend on lots of factors.
The actual numbers that I have seen in reviews, indicate a slightly less than 5% improvement in gaming latency. If you have already spent enough to max out your video, then maybe it's worth it to you.