Much of a muchness really. It depends what standard you are. If you're beginner/intermed. then you wouldnt notice the difference between the two boards, however I think O'Brien might make better bindings. They've been around a lot longer too.
I don't know much about O'Brien but I was mates with the guy who was Liquid Force South Africa and saw a lot of their wake product line and specs. I also saw how much effort they put into R&D and how serious they are about their product and I am well impressed. I have no commercial interest by the way, unless it's my mate's shout at the bar...
I've also had 3 Liquid Force kiteboards now and reckon they're fantastic. A little heavy perhaps, but a solid construction.
