You need to tell us what kind of riding you do to give us the best answer in my opinon. The powerclaw is probably the best all around track out there. The A20 was made specifically for light fluffy powder, so it rocks in light fluffy powder (probably better than the powerclaw, but that is up for discussion), but on hardpack (unless turned around backwards, in which case hooks up awesome) can be down right scary. When the A20 is turned around backwards, it is great on hardpack (except for downhill stopping), and will be terrible in light fluffy powder. The challenger also is a good all around track, but not nearly as good as the powerclaw. The other thing to consider is price (if that matters to you). The A20 will probably by far be cheaper than the other two, then I'd guess the challenger and finally the powerclaw the most expensive. I ride with an A20 and love it, but I live for the deep powder, and have gotten use to it in other conditions to where I'm ok with it, but that is just me. Most people hate the A20, but I think most people didn't understand what the A20 was made and designed for. It was a purpose built track for deep powder. You give up the all around good track for a track that is awesome in deep fluffy powder. Just my $.02 or was that $.10?