I haven't heard great things about the Hardware store brand epoxy coatings myself. I coated my garage with U-Coat-It brand and the stuff is great. I have not had any peeling/lifting etc. even with lots of heavy use (jack stands, jacks etc.). The coating is great and cleans up easily.
I have heard that prep work is the most important part, especially if it's an older garage that has lots of oil stains, etc. My garage was new so the prep work was pretty easy; just borrowed a power washer and used the muriatic acid to etch the floor first.
