I've used the DeathAdder for a proper session now and it's really nice, I find I can aim a lot easier with it. I got the 3500dpi one (didn't realise there was any other) and I'm surprised that I'm using full powaaa (re:dpi). Razer have done a stand-up job as far as I'm concerned.
For optimum performance, you should have the dpi set to maximum and the use the OS to slow it down to your preferred speed.
This gives maximum response, and accuracy, all at the speed your hand/brain can deal with
