Not gonna lie, my experience with mouse-only playing has usually always been "Oops, I played 3 months and now the buttons don't click properly anymore". Some of the better gaming mice have lasted a little longer, but they all eventually come to a point where, at the very least, the buttons don't "rebound" properly anymore and clicking fast streams or even just stacks becomes impossible because the buttons don't rebound as fast as you're trying to click them.
Basically, I really dislike soft buttons on my mice, but no matter what I do, they all kind of "wear down" in hardness after only a few weeks of playing. I'd really like to know if there's any mice out there with an actual spring mechanism under the buttons, kind of like the ones mechanical keyboards have.
As for the IntelliMouse, I've never had it myself, but I've seen it mentioned by a few really good mouse-only players, so it might be a good idea to try it out.