Everything JF_o97 said is true.
Now, if you wanna get a new mouse I'm not sure about the wireless models; apparently the response time isn't consistent with those. Mouse pads are very important, but you also have to ask yourself how do you control your mouse? With solely your fingers (your hand resting in one spot on the desk) or with full hand (your hand not touching the desk at all, but your arm might be). If you play 'fingers' you should invest in a rather small and flat mouse, while if you play 'hand' you should invest in a larger mouse with a hump (like G700).
I for example have the
Logitech G9 and sometimes I switch to an
A4 X747. G9 is the smallest gaming mouse I've seen so far, and I have a pretty big hand so I play fingers on it. It has an 'interchangeable grip' (video) and I've switched to a grip without the hump on it. The X747 is more leaned towards a 'hand' grip and I use it just to learn to aim differently.
Some mouses are more universal like the M950 you linked, but then some are strictly made for either big hands or for a complete 'hand' control (MS Sidewinder. Seymour has biiiig hands). There is no single best mouse for everyone and every game, but eventually you'll find something for yourself.