I have the Yongnuo Y-622C E-TTL triggers, and I have no problem with syncing even at 1/250th. No black at the bottom of the frame. I am no more limited than I was with either 60D or 5DII. I should note, however, that the flashs that I just tested (580EXII) automatically go into High Speed sync mode at 1/200th or more. For my purposes that has not been an issue, although I read that flash output is somewhat reduced in that mode. I am typically dialing down flash output anyway as I prefer a softer look. I don't think that my workflow is at all changed by the sync speed.
The same flash mounted on the camera does limit shutter speed to 1/180th unless HSS is enabled.