I'm guessing you mean a Directional Twin vs. a True twin? The big advantage of the True twin is that both side are exactly the same, meaning if you like to ride switch a lot or land tricks in switch a lot it's going to help you out because your switch riding will mimic your normal stance riding, especially when paired with a true-duck stance or close to one.
A directional twin keeps the design close to what a true twin has, but will will differ a little bit between the tip and the tail and sometimes have a natural setback to your stance. I have a directional-twin and a true-twin, and I will admit that the true-twin is easier to ride switch, probably mostly because I have a bit of a setback on the directional which means when I ride switch more weight is actually on the front of the board instead of the back. If you use a centered stance however, this isn't as noticable.
You can really go either way, a True-Twin will still bomb down the mountain, but just not as well as a directional, and vice-versa for park/tricks.
I hate to be an east-coast hater, but if you board in Michigan I would probably just grab a true-twin since the hills there are mellow and you probably wouldn't be able to take much advantage of the directional. I'd think you'd get more fun out of the true-twin.
PowderHound and TreeNinja
Last edited by HoboMaster; 12-14-2010 at 11:38 AM.