I´ve skied Step up´s all last season, and they are really durable, they have two carbon plates plus the 7peace wood core which makes them stiffer but also more durable then the afterbang´s!
My topsheet never split up, and they keept the flex because of those 2carbon plates!
Otherwhise I can tell you that the next years step up´s are not a skate deck construction ski anymore they have real sidewalls and are super good and durable, if ur afraid of the skate deck construction!
Otherwhise I would really recommend the Chronics which is by now the same ski then the cryptonites, a little wider then the step ups and because of that better for going all over the mountain...
step up´s are kind of the older chronics cause they are more slim and not as wide as the new chronics...
they are good for big and also small jumps and rail, if you wanna go all over the mountain ski some slope for example and hit the park and rails take the chronics, sick ass ski!