Intended Use
This program is intended for performing simple automation tasks in Windows. It is not intended as the "be-all and end-all" of scripting. When performing complex tasks (registry manipulation, text file parsing, complex loops, etc.) I would recommend using AutoIt in conjunction with a fully-fledged scripting language (such as WSH or Kixtart - both free) and using AutoIt to "fill in the gaps". The current ethos of AutoIt is "If it can't be done on a single line - it's probably too complicated". This approach has worked well so far, and helped to keep the size of AutoIt down (it is a tiny executable!).
I personally use AutoIt for large PC rollouts. I use Kixtart/WSH as a "back-end" to copy files, run files, edit the registry and then use it to call AutoIt when I need to perform configurations that can only be usually achieved by manual input (software installation, configuring control panel, changing drive letters, etc.).