I used PW ControlTL for at least two years before the 600EX-RT became available.
I found that they worked well with Nissin Di866 speedlites on the FlexTT5s and a 580EXII on the Mini on camera.
What most people forget, or disregard, is that the ControlTL firmware sits between the camera and the speedlites. The features available are dependent on the firmware. For the most part that's not a problem because they have implemented the Canon ETTL features.
That also means that the capabilities are limited by the ControlTL. i.e. putting a 600EX-RT on the flex turns it into a 580EXII.
A 7D does not take full advantage of 600EX-RT capabilities.
Given what has evolved in ETTL triggers over the past couple of years, I'd suggest looking at YN-622 triggers until you have a camera that fully supports the 600EX-RT's capabilities. They are much less expensive than the Pocket Wizards and work better, in my opinion.
Youngnou has recently announced a YN-622 trigger with LCD screen for controlling the system without having to go into the camera speedlite menu.