is this like AHK, in terms of what it can do or how it can do it?!
I suppose that's like asking whether two photo editing software packages are alike: as they are both intended for similar purposes, there will be an overlap, however that doesn't mean things function identically, or that either package won't have unique features.
E.G. when it comes to speech recognition, I assume VoiceAttack would likely offer a broader set of features.
This user-created addon may be of interest, in this regard.
Is there a free version or just the trial?
There is a trial/demo version intended for evaluation. There is no perpetual "free" version.