If you're going to be racing, then that's a different story. But if you're going to just be riding on multiple terrains, I'd definitely go with the DS b/c it will hold up a lot better on the rougher terrains (Allamuchy & Ringwood for instance) and it will do just fine on the smoother stuff (Lewis Morris and Hartshorne for instance). Ideally I'd like to have both b/c riding Hartshorne with a dualie is major overkill, but I'll take the lost power in that ride over the extra shock absorption that a dualie gives me on a rougher ride. I remember riding Allamuchy with a hardtail when I first started riding and my body would just take a beaten. It still beats me down with the dualie, but to a much lesser degree.