I have a 2012 model Crossmax ST wheelset. There are two disadvantages to the Crossmax ST 2010 model.
1. it's narrow, 19mm wide ID. this used to be normal but today it's on the narrow side and Mavic recommends no larger than a 2.3" wide tire. forget about DH tires; there are some AM tires that are pretty massive and they won't be ideal on a narrow rim. the current model Crossmax ST is still this same size and I have used an average to slightly undersized 2.3" Ground Control and it worked fine. the sidewall profile is definitely better on a narrower tire, though.
2. The hub is the older style which has few points of engagement than the new ITS-4 hub that I believe the Crossmax ST 26" got in either 2011 or 2012. (29" definitely got ITS-4 in 2013MY.) I am pretty sure the older hub is 15deg and the ITS-4 is 7.5deg. Some people are annoyed by slow-engaging hubs. Some never notice.
Unless you have something go into the wheel or you're a very heavy rider, you are very unlikely to break spokes on a Mavic Crossmax ST wheel. It's very strong in general, but especially in comparison to other wheelsets of similar weight. It has a patented rim and spoke design that is responsible for this strength. So, personally, I don't really care that the spokes are proprietary.