Honestly, it is worth it for every day computing: browsing the web, reading documents, and once you get better with them, even moving text around from a word document to another spot. The slimblade is my daily driver and I use it 90% of the time for these tasks. 10% goes to my vertical mouse because some things feel faster and more precise with it.
For gaming? I play things where aiming is not that big of a deal, like Diablo, where it's just a clickfest and aiming doesn't matter, I can't do it with a trackball. I've tried to game with: slimblade, ploopy and deft pro. I sucked. I couldn't get used to it. So I just game with my vertical mouse instead. Can you game? Yes, but it's hard to fight against years of training. Some do it and you can see their videos on youtube. But it depends on the games you play and how much time you can devote to re-learning how to do it.
General computer use? Love it. Easy to adjust if you put all other input devices away and then add the mouse when needed.
Gaming? Ughhh. I suck at it but you might be better with it.