Yes it's the difference between being bottom of the scoreboard or not.
My 2c:
- laser is better than optical because it more accurately tracks the surface under the mouse, always get laser and pair it with a good surface (e.g. razer goliathus)
- DPI does help, but you don't need as much as some mice offer. e.g. my Mamba can do 5600 I think, but I run it at 2500 and most people struggle to control that. to clarify, this means you can get the same movement on the screen with a smaller movement of the mouse, because the mouse can detect smaller movements based on its DPI. So more DPI isn't necessarily better, it lets you customise the DPI to allow you smaller movements which is completely personal preference. However, in terms of time - you can do a smaller movement much quicker than you can do a larger movement - so really you should turn the DPI up a bit and move from the wrist.
- comfort is important, usually you get a better shape from a gaming mouse than you would from a cheapo standard mouse. That's especially important if you're clutching it for long periods of time, which as a gamer you are.
- buttons are personal preference. I like to have a thumb button for voice comms and then just standard buttons. changing DPI on the fly has never been something I've needed.
- wireless is god awful, even on the Mamba - ALWAYS game on a wired mouse over USB. Gaming mice do/should come with software which lets you overclock your USB bus. You should make use of this - the difference is huge. You can go up to 1000hz, but I find 500hz to be just fine. This is the time it takes between when you start moving the mouse and when the computer realises you've started moving it -
1000hz = 1ms, 500hz = 2ms, USB = 125hz = 8ms, PS2 = 80hz = 12.5ms