I have pro box on my fish, don't really like them although the idea is cool (being able to adjust the fins). My problem with them that is that the screws holding the fins in only go in through a tiny bit of plastic that can break easily. If this happens you need to replace the whole box which really sucks. And from what I can tell most shapers are not too comfortable in installing and repairing the kits.
Futures all the way. I just got a new fish with FCS and am bummed i didn't wait for one with Futures. I used FCS for years and they offer nice setups. However I hate how there is always a gap at the base of the fin. It seems almost every fin I try has a frickin gap between the fin box and the the fin on my boards. Futures solved this problem and only have one screw. Every Future fin locks in perfect with no gaps at the base and they have awesome templates for all board designs. Go Future skip on FCS