First of all I don't want to say that Optical is better than Laser. I might have used some wrong phrases^^ I mean that I'm happier with optical mouses than with laser, but each to their own.
Yeah I had the Xai for a while but sold it and got the Kinzu.
Don't know how I'm supposed to explain this. My English isn't what it used to be.
However, I'll give it a shot.
So far almost every Laser mouse I had became "buggy" after a few months or years and the laser didn't work properly anymore. I noticed it when I was using it on the windows homescreen, when the cursor was jumping around a bit when I tried to hit random icons. I couldn't draw a solid line it was fluctuating.
Here is what I mean:
I purposely messed up the upper line, it wasn't THAT bad but still very much noticable in and out-game. However, that's what it looked like using, for example, the Xai. I used different mouse pads and cleaned everything to make sure it's not the surface that was dirty or anything. Yet it still was fucked up...
The lower line is drawn free handed! Didn't use the solid line tool.
Dipsy-doodling all over the place I decided to switch to optical mice after a few suggestions by various other players and had no problem whatsoever, whether be it the sensor or the mouse in general.
Those are my 2 cents. If you prefer other mice, go for it and buy the one's you like. I mean it's your decision.