Same here. Use mine for WoW, not a problem. Would like a little more customization on the buttons but that's it.
Ball gets clogged, but just takes a minute or two to clean.
Generally, that's true.
But, before I quit using mine, it got to the point where I would invest 20 minutes to scrubbing, cleaning, scrolling all different directions and so on over and over and over again using a clean cloth and some rubbing alcohol.
It just gets a build-up under the ball, and after a while there's nothing you can do to get it all out.
I finally got tired of spending 20 minutes every week on my mouse. So, I cleaned it one more time and gave it to my wife.
My wife uses her computer less, and I haven't had to clean it since. Also, the Microsoft Mouse that I use now hasn't had to be cleaned at all either.
So, I used my MightyMouse for a year and a half. It survived the first 3 months without needing cleaned. After that, it needed about 2 or 3 minutes of cleaning every week for about 3 months or so. After that (and until I quit using it) I spent about 20 minutes a week cleaning it.
Of course, I could get it cleaned and working in less than 20 minutes. But, it would take 20 minutes of cleaning to restore not only functionality but also that nice smooth scrolling feel that it is supposed to have. It would scroll a bit rough until it was thoroughly and repeatedly cleaned.
The main issue, is that the oils from your fingers transfer to the ball. And, the ball is the mechanical surface. The sensor that the ball rolls on doesn't register the scrolling once the ball is covered in oil.
Other mice use wheels that are mounted on an axis / axle type pin. So, the pin runs through the wheel, and is turned when you turn the wheel. So, the oil from your fingers won't affect wheel mice since the wheel is not the part responsible for making contact with the sensors.