Value wise the Pro 2's are hard to beat, I have them built up to DT EX500's and enjoy them very much. But my buddy has 721's laced to Hadleys and that wheelset is pretty much the ultimate as far as anyone or anything is concerned.
I have two sets of crossmax SX wheels (xc and dh tires) and I absolutely love them. They are stiff, strong and I haven't had any issues with the hubs (yet). If they can hold up to the abuse I give them (215lbs hitting jumps under 20' and drops under 10') they should hold up for most any rider.
How long have you had them? A problem with those wheels is that once the hub is shot you have to buy a new wheel. (I think?)
This is my second season running them, I got one flat spot in the front wheel from hitting a rock while running 20psi. It flatted the tire but I was able to hit the spot out with a hammer and it is almost completely gone and the wheelset still holds air setup tubeless. I only had to true the wheels once; they have been super low maintainance. I have yet to have a hub issue but I would be shocked if you were not able to replace just the hub if you had an issue. I would call mavic to check before you buy them (it is either 1-888-usmavic or 1-888-go-mavic i am not sure which one). In any event I would buy their one year no questions asked warranty, I never had to use it but it is a good piece of mind. I have the older version btw (pre its-4)