I really did want to like this mouse. The construction on it feels great. Software is solid. I love the buttons right next the right and left click buttons. However I just can't get used to it. Been using it all week and coming from a corsair MMO mouse to this EVGA mouse is just rough. I can't seem to get the button config down. button 9, 10 are way out of the way.
 
Here's hoping that revision 2.0 of this mouse sticks with the tried and true formula of 12 on the side. Much easier that way.
 
Good luck for those that can use it. I'm going back to my corsair mouse. Going to use this one for another rig.

jumblo
I can't seem to get the button config down. button 9, 10 are way out of the way.

I have found that you need to use a claw grip with the bottom of your palm resting on the "E" Logo to hit the 9 and 10 buttons.  But, then you have to switch your palm resting to hit the 7 8 and 4 buttons.
 
I strongly suggest to EVGA to dev a new mouse that has 4 rows of buttons instead of 3 with a higher profile to make in ergonomic for your palm. Since no one has done that yet, I am curious how it would feel.

My x15 feels cheap and the mouse is warped or something because it wobbles when i move it. Also I agree about the buttons being way out of the way. I wanted to like it too coming from a g600. Didn't care for the Corsair mmo mouse though since it doesn't have that 3rd click button on the left. I have come to rely on that which is way the x15 was so appealing to me.

I love the e-shift button like the g600, as well as buttons 11 and 12 next to the left click.  Buttons 9 and 10 are so far away, my thumb will never reach them.
 
I am having a problem with the software.  Any macro i assign to a button has a 1 second lag before the macro is performed.  Yes, i've modified the macro and made each step have 0ms delay, I've even clicked on the "setup" section, enabled the "delay" and set that to 0ms, but even that doesn't work.  Must be an issue with the software.

I agree with the claw grip. I like the corsair because I could move the keypad back and forth on the side to where it suits my hand config the best. I wish it had the extra button next to the left click. Like I said, I wanted to like the EVGA X15 so badly, however it just fell short in my opinion.

How do the thumb buttons feel after hours of mmo-ing?

My thumbs can only reach the bottom 3 rows, but the buttons i can reach are ok.  I'm not sure i like the layout, however.  It seems i have to adjust the way my hand is positioned in order to push certain buttons, like 2, 3, 4, 7 and 8.

If you're curious and the sale is still going on, I'd say pick one up to try out. It's only $39.99 on sale. I can think of a lot worse and less rewarding things I've spent 40 bucks on in my lifetime.

jumblo
If you're curious and the sale is still going on, I'd say pick one up to try out. It's only $39.99 on sale. I can think of a lot worse and less rewarding things I've spent 40 bucks on in my lifetime.

I was almost about to snag it, but unfortunately the sale seems to be US-only (it's between $88-99 here in Canada). 

It still seems like one of the best options since unfortunately the number of MMO mice seems to have become a lot less over the years. It does seem to be a pretty good mouse but it also seems that it takes some getting used to and the 9 and 10 are pretty far up on the mouse.