Blimey, this thread's been around a while now.
I just got my hands on some XBee-Pro ZB Modules (2 mile range) which as they have gone down in price are now very similar priced to these modules (possibly slightly cheaper now for the range), I haven't done any further comparisons yet though...
From a quick look, I think the features on the XBees still exceed these but not by a lot 
Possibly other users would like them but until this thread, I had never heard of them. Everyone who knows anything about wireless data has heard of XBees.
Especially if they do a side by side comparison between XBees.
Any chance you could do a comparison between these and the XBee Pro-ZB modules?
Mowcius