I wonder how the phottix system is. It seems like that's the one that Gary Fong uses the most in older videos. Only challenge is that it seems like it's hard to find in stock in sony MIS mount, and it's somewhat pricy - but about comparable to pocket wizard.
I have the di700a and air commander setup, and just use optical slave for my other lights and it's ok, not great. I've used it on paid shoots and 80% of the time I don't have issues with it - I just make it a point to re-pair the lights before I start shooting. Sometimes the air commander has issues getting a signal out of confined spaces though which is annoying. Also agree with the other poster that the mount itself on the MIS shoe seems way too flimsy - the di700 on camera would be way too fragile I think for real professional use, but that's less a ding on the nissin and more about the mount design itself. If I did a lot of running and gunning, I'd likely invest in an offset flash rig anyways that mounts the lite next to the camera on a sturdier platform and just use a sync cable.
I don't think we can rely on Sony for a professional light system, but would love to be proven wrong. The reality also is that even stuff like pocket wizards have issues with syncing and firing too.
Nissin was supposed to release an RF receiver compatible with the air commander a few months ago, but haven't seen anything yet. I'd be more inclined to stick with the nissin system longer term if that's released because I could then easily integrate HSS with say an einstein strobe. The actual di700 speedlite is ok and has good power, but it has quirks that bug me a lot. You have to control the zoom off camera through the air commander, which is idiotic. The air commander itself eats AAA batteries like crazy - you have to use eneloops or a comparable high capacity battery on the trigger otherwise you'll be replacing batteries on the thing every hour
