Keyclone has more features, requires less work, is pausable without having to go to the tray and click to turn on/off, and better support; less work, more functionality in a nutshell. Plus it automatically passes keys and can black or whitelist them at any time through a very very simple interface to add/remove, rather than creating/editing a script and having to re-run it every single time you change it.

I used AHK for quite awhile before I finally gave in and bought Keyclone and do not regret it one bit I pretty much just whitelist my movement keys and autorun which i hit alot then leave it running unpaused so all 3 boomkin attack and kill things; if i need to chat or simply shift/buff with 1 druid instead of all 3, I simply push Pause, and bam, back to controlling just the front window, do what i need, then hit Pause again to reenable it, no "Is this your main wow window?" and min/maximizing required like AHK does