I do have the OCC system, not the current one, I have the sparmax with the sp 35 gun.
I recently took the Temptu intro class.
What I notice, the Temptu compresser is better. You can use it with both. As far as the makeup itself, I do like the temptu and OCC, for different reasons. I also use Graftobian. OCC and Graftobian are more matte.
If you both have specific questions, I'll try to answer as best I can from a newbie airbrush artist's view. lol