I bought the stuff from Lowe's as was recco'd by several folks that I know who work on cars. Fairly inexpensive compared to other coatings. It also depends on whether your garage is actually a "working garage" vs something more "up scale". THat being said, as long as the surface is prepped right, just like a good paint job, your result should come out and last a good long while.
BTW, I'm always getting large pieces of coardboard when folks get new applicances and such to place underneath my cars. Just makes the coating last that much longer and it's a little warmer than bare concrete.