I finally got PocketWizard to take my Flex-system back after over three years with email back and forth because they don't work. They replaced the radio's and I replaced my flashes, still didn't help. So they have been great in assisting me and now refunding me. So for me, and many others, this is the system to AVOID at all cost. Luckily there's an answer, it's the Phottix Odin. Set you back about one third (!!) and put batteries in and start shooting. It NEVER misses. YOu can do everything the PW's can and in addition you can remote-control the zoom-spread of the flashhead and (when sensible) it will trigger the AF-assist on your remote-flashes.
It's the only option I have tried that makes me able to shoot at 1/8000s with my studioflashes (Elinchrome). They've included those sync-cables.
After shortening my life with about 10 years of PW-BS, this made me want to use my lights again. It just frikkin' works! 100% of the time. Exactly as promised without spending hours in software to "tune" them. PW really dropped the ball with the Flex system.
Oh, and yes, the ETTL of the Phottix is at least as good as Canon's for the little I have tried it.