I use PWs daily in the studio. We are only using them to fire Speedotrons. We have lots of the MultiMax and Plus transceivers. I personally just purchased the Odin from Phottix to fire a group of Canon Speedlights. I need the HSS function and found that these are the only reliable devices to achieve it. I tried hardwire, IR, and finally these wireless units to achieve a consistant HSS set. I had heard and seen the problems people were having with the PW flexis and decided to go the Phottix route. Glad I did. They work great.
Phottix just announced their version of the Canon 580EX II speedlight. They are aiming for a Q4 availability. Hope the price point is in the reasonable line.