I've been playing with a pair of Yongnuo YN-622C wireless flash trigger transceivers, with my Canon 5DIII and an old 550EX flash (although it was designed to work with the EX Mk II flashes). While bigger and more expensive than the YN-603's that I tried first, I could not sync faster than 1/160 with the 603's. The 622C's will do high speed sync with my camera at any shutter speed I set. I can set the flash for E-TTL or manual, while the 603's are just manual.
With a $10 pistol grip and cold shoe, I can easily hand hold the flash with a homebrew bouncer/diffuser and get nice depth and texture out of flowers. The high speed sync lets me really darken the background and make the flowers pop.
The transceivers have their switches and buttons on the side, unlike the 603's, which hide the on-off switch under the flash so that you have to unmount the flash to get at the switch. The 622's also have tightening wheels that safely lock the transceivers to the hot shoe, also unlike the 603's.
The construction is reasonably good, and the batteries used are AA cells. You can also send focus-assist beams from them. I do not work for Yongnuo or Amazon, but am having such a good time with the YN-622C's that I wanted to share this here. The price on Amazon is about $90 for a set of 2 transceivers.