Well, I used the 622 triggers yesterday at a wedding, first event usage. My only problem was some issues with the on-camera flash in eTTL mode. It seemed to occasionally produce an 'over-exposure', about one shot in 10, and in one stretch it was even more frequent, almost one in five (14 shots out of 78). I finally switched the on-camera flash to a manual setting, everything worked perfectly after that (was using 'mix' mode for the last sequence of 78 shots). The on-camera flash that was producing the overexposed shots is my 580exII, which has been an extremely reliable flash that has never given me any problems at all. I'll experiment some more with it, but it does appear to me that the 'pass-through' to the on-camera flash isn't quite as consistent as just having the flash mounted onto the camera directly. When I had everything in manual settings, it worked flawlessly, and it's nice to have total control over the manual power settings from the camera. In all, I'm satisfied with it as it appears to work, for now. I switched from using Radio Popper units (the original P1 units, which had about a 90% success rate of firing the off-camera flashes), but eventually I think I'll be upgrading to the 600ex-RT flashes, when I'm able to afford them. Until then, the YN622 seem to be very serviceable, with a little bit of instability in eTTL mode, perhaps.