Maybe I am extra tolerant, but I think I find 99% of mice, no matter how cheap, fully comfortable.
Two exceptions though:
- I don't like one-button mice (Apple?).
- The god-awful black IBM mouse from years ago ("IBM Scrollpoint mouse" I think it was called), where there was kind of blue "thumbstick" instead of the mouse wheel. I still have couple of those around, and they are awful if you ever wanted to use the mouse wheel, or press the wheel (as the third mouse button). What the heck was that design about?
http://reviews.cnet.com/mice/ibm-scrollpoint-mouse/4505-3148_7-30834898.html Well, ok, now that I start thinking about it, I dislike if the mouse wheel is quite loud. I have one mouse at work which gives this "RT-RT-RT-RT-RT-RT" sound when I use the mouse wheel to scroll web pages. Sometimes even the clicks from the other two mouse buttons might be too audible. But mostly these are ok, smooth and silent.
For gaming, I'd like to have one extra mouse button for thumb. I have one such mouse at home (now defunct), and I haven't been arsed to buy a replacement as I have more than enough spare mice with the normal two buttons + wheel.