Absolutely! I don't think anything else should be sold but variable speed anymore (but I know that's a long ways away from happening).
Are you familiar with the comfort-R settings that A/S and Trane have? It cools the coil down to remove humidity then ramps up later if needed. It also can do that in heating aswell to help cure the problem of "the air isn't hot enough coming out of the vents when the heat pump runs".