This is the 3rd post I see about ThickButtons, and since I'm familiar I guess I'm an evangelist. I don't consider myself ham-fingered but I was making way too many errors with the stock keyboard. I'd swear up and down I was hitting the "i" but kept getting an "o" (and so I'd be swearing up and down yeah).
ThickButtons is incredibly smart at predicting what word you might be typing, so what keys you might want to press next. When it can't guess, it reverts to all keys the same size. It's cut down on my errors dramatically.
I might try Swype or its clones but right now I couldn't work without ThickButtons.