I have been searching now for 3 months for the closest to perfect mouse for me.
I have tried, Deathadder 3.5g, Xai, G9x, G500, WMO, 3.0, Mx518, Imperator.

I will describe the perfect mouse. I am looking for more options to choose from then what I have already tried. my perfect mouse in order of priorities.

1. Has a sensor offering perfect control (ABSOLUTELY ZERO ACCELERATION) at speeds of up to 2.3m/s. *approx - ( i think this is the fastest i turn.. possibly 2.6m/s. I use ultra low 65-85 cm/360.
2. ZERO prediction or drift control or angle snapping (whatever you want to call it :) ).
3. Buttons that respond well and quickly.
4. Lift off distance that is very low.
5. Lightweight. Solid feel. Good weight distribution/center of gravity. Sensor in center.
6. Nice feel in hand *I understand this is completely subjective*. Including a texture which does not slip easily (sweat).
7. Nice glide with no scraping - *i know this can be changed*
8. 5 or more buttons.

I dont care about dpi switching or having any dpi higher then 1800. Normally I use 400 or 450, but would like to have the option to do higher for whenever the rare case I might wish to do so. Yet I am fine with being locked at 450 or 400 dpi if i must.

I'm aware that I will probably have to compromise :).

Now to explain a little about what i felt with what ive tried.

MWO - I feel it is great and light but you lose control at 1.5m/s. It also feels cheap and the buttons do not respond as fast as the others. Yes i overclocked to 1000hz.

3.0 - To big for me. I seem to prefer smaller and lighter mouses. Buttons respond slightly better then mwo. Also skips at 1.5m/s.

Deathadder 3.5g - This was very confusing to me as I read massively about the original. The original supposedly tracks up to 3.92m/s at 1800 and still 2.3m/s at 450. The new one tracks very very well at 450, but at 900 and 1800 it is completely useless - losing tracking control very easily. 3500 seems to be better then 900 and 1800 but not as good as 450. ( I will NEVER use 3500.) While I will use it at 450 almost all of the time this is not a huge deal to me, but would like to have to other dpis available to use properly or not there at all. Biggest issue with deathadder is it is scraping HARD on my pad and i have tried 3 different ones. It also feels to heavy and big in general - and the sides are horribly slick and terrible. If i kept this id have to stay at 450, raise it up massively to not scrap, and fix the sides from being so slippery. - i know all of this is doable. The buttons are great though and respond well.

Mx518 - used it for years and only wished it glided better, was lighter and didn't have prediction. After using many mice without prediction I refuse to go back. feeling was pretty good in my hand but not amazing.

Imperator - Skipping this because sensor was worthless for me.

G500 - To big and bulky and felt cheap - didnt like the glide or the sensor position. *Discuss sensor later. Did have nice texture for sweat issues though.

G9x - Didn't like either grip - and I don't even like the idea of having multiple grips and weights. Doesn't feel as solid because of this. While I could grow accustomed to the fat man grip using the claw grip eventually.... it was not my choice. glide is also sub par. The g9x mouse 1 button felt very great though and clicks with minimal effort (i like that). *Discuss Sensor later

Xai - The xai feels damn near perfect. Perfect weight, weight balance, glide. Buttons on xai are a tiny bit hard to press - I would prefer the deathadder/g9x buttons. This was the only downside to the feeling of the xai which other then that was phenomenal. *sensor discussion below

To discuss the sensor used in Xai/g9x/g500 - overall I have to say that the laser feels more responsive. This could be to due to the fps - i'm not sure. The issue I had with all of these mice is ... they simply don't feel as consistent. *BTW IM USING 1000HZ on all tests*. I am aware that over 1m/s the xai will positively accelerate, and the g9x/g500 will also do a little accelerating after 1m/s. Without/Before doing any research and discovering about the positive acceleration issue - i still kept saying one thing - It doesn't feel as consistent.

In conclusion - If the xai felt perfectly consistent up to 2.3m/s I'd buy 10 of them. NOT even sure if this sensor can be firmware upgraded to do that. Possibly I just have to get used to it. - Still deciding :).
The Deathadder 3.5g at 450 is the only one I felt consistent at the speeds I use, but unfortunately I dont like the feel to much and it scraps horribly on the pad (tried 5 pads, and 3 deathadders (all 3.5g)) and slips around in my hand - I may have to just modify a deathadder bigtime. Because of the issue I'm having with the 3.5g I have JUST ORDERED an 1800 dpi deathadder to see what the difference is in sensor at other dpis then 450.

These are the mice I am currently considering getting to COMPLETELY rule out all possible options.

1. Razer Abyssus - I know it uses same sensor as 3.5g DA.
2. QPAD 5k - I know it uses same sensor as xai.
3. Kinzu - I've heard theres a lot of issues.
4.. Logitech mx518 - I have heard their are mx518s that exist without prediction.

Mice i'm curious about - wondering about their performance at high speeds and if they have prediction or not.
1. Steelseries Ikari Optical
2. Razer Diamondback 3g

To make this ultra long story short - From everything I know my best bets are
1. The 3.5g deathadder LOCKED at 450 and modify the crap out of it (skates/sides).
2. Abyssus locked at 450
3. Original deathadder modified.
4. Get used to the odd inconsistent feeling of the xai.
5. Deal with the overall cheap feel and buttons of the mwo and simply get used to the Negative accel at 1.5m/s.

I hope that my experiences can shed some light for anyone considering any of these mice. I also hope that other users can shed some light for me with their feelings and opinions. I am open to any and all suggestions and appreciate any input. THANK YOU VERY MUCH! :).