I've commuted with a cx bike for the past year and have been happy with it. The benefit is lighter weight than mtnbike, you can gear it for the streets, and plus you have canti brakes for better braking and fits fat tires. The only drawback is perhaps lack of brazeons for racks, but I've gone with a Vaude backpack anyway, so not an issue for me. I have some knockoff Korean alum frame I built up, like Specialized S-works geometry.