Kind of a bummer that you don't get independent group control in TTL mode. About 6 weeks ago I picked up the Phottix Odin triggers, they're more money ($330 for the 'starter kit' of one transmitter and one receiver, $130 for each additional receiver) but they offer 3 groups with full independent control of each group, in any combination of TTL and manual or A:B ratio mode. Otherwise, from what you wrote they seem comparable. Long range, high speed sync, works through walls, etc.
Maybe I should write a similar review of those.

@Novicesnapper - AA batteries. I had no problem using eneloops, so I think any higher-rated rechargeables are probably fine.

@Molotov - yeah, I considered the Odins. They were, in fact the first ettl option I consisdered. I read plenty of good reviews of the Phottix product, but In the end, I decided to give the PK's a try because they're ~1/3 the price. I knew they wouldn't do ratios in ettl, but that wasn't dealbreaker for me (especially as they can do ratios in manual mode). In the kinds of places I need radio triggers to solve line-of-sight issues with the STE2 trigger and IR communication, I typically don't need multiple flashes or subtle adjustment between flashes; that's more something I need when I'm shooting studio-style indoors, at which point line-of-sight is pretty easy to maintain and I can use the IR system of my Canon set-up as needed.

Thanks Diva, been busy here, not able to spend as much time as I would like too on my hobby. I did get my triggers in, finally, these are so nice. I threw some energizer rechargebles, ni cads I think, into mine and they work great. For the differance in price between PW's and these, for my purposes, I could buy a better body or better glass. The steel foot on transmitter was a nice touch, and the oversized foot for the receiver also. I'm very pleased so far.