I use both styles of maps. I dig the Alien RPG maps, and my players have no issues with them. I'll occasionally use regular battlemaps just for some scenery, but even then, I'll stick with the games zone system instead of relying on map grid sizes.
Besides the stuff offered in the store, there are tons of free sci fi tiles out there for building your own maps, as well as some cheap scifi tile packs on DriveThruRPG. Lots of stuff on Reddit and Pinterest. Harness your Google Fu!