Before I got my MX518, everybody seem to say about how gaming mouse can give your more headshots etc. I was skeptical at that time because to me, the only difference of a gaming mouse is it is more sensitive, and maybe better ergonomics compared to cheap mouse.

But when I got my MX518 and play L4D, really my headshots almost doubled! I don't know how it happened, but it just happened.

I agree that although gaming mouse helps, the most important part is still personal skill la. MX518 or not, I still get owned in CS all the time.