Yeah AutoIt and AutoHotKey are two amazing utilities. I tend to use AutoHotKey more for "shell tweaks" (hotkeys, always-running windows enhancements) and AutoIt for scripting. AutoHotKey has a very simple and powerful text replacement/hotkey configuration that AutoIt just seems to make overly complex (relatively I mean). But, I just cant get used to the AutoHotKey syntax! I know it's supposed to make things easier, and maybe it is if you've never coded before, but it seems much more fluid (like, sometimes variables need to be enclosed by %, sometimes not, sometimes you need to use :=, other times just =). I like the more rigid structure of AutoIt. It's closer to the VBA I'm accustomed to.
All that blabber having been said, as mouser said, they are both extremely powerful and I'm not sure one is "better" than the other. Test drive them both for a while and see what you use each one for!!