MD, there is actually very little difference in the hull design on the X and M, with the M being a few degrees deeper V'd. The M will have a dagger board while the X has a swing keel (center board). This is the most important difference for us pertaining to the bottom. A dagger board will not move if you strike something. If you strike it hard enough you will damage either the dagger or the trunk or both. A swing keel will usually swing upwards and bounce over whatever you hit unless you are going backwards. When we were searching for a boat we sailed a brand new M in Miami. I later drove to Las Vegas to look at our X. Sailing characteristics are very similar as is the performance under power. Ultimately we choose the X because of the roomier cockpit and, in our opinion, better layout of the cabin. The standing room head is a nice bonus of the X when you have guests on board who want a little privacy. Ultimately, I would recommend checking out both and seeing which model fits your needs best.