I've been using the Relay pros on my bc setup. The heel cup is comfortable and I honestly don't notice any performance difference with the flex. The biggest bitch with Salomon I have is their damn ratchets like to jam up when you try to release them. Otherwise, it's been a super solid binder. I just got a set of Union Force DLX's. I am debating on setting them on my bc setup or resort ride. If I do the resort board, I am going to have to wait until next week to try them out.