First question is what do you use your garage for? Parking cars, Storage or do you use it as a work shop? The reason I asked is a friend spent allot of money getting his 3 car garage floor epoxy coated, only to find out the metal chop saw and welding sparks left burn marks on his floor. I never thought about it before and I guess he did not either. When he called the company to come out and look at it they said it was not the epoxy that was damaged, but the second clear coating they apply on top of the epoxy color coating.
Now with that said I know someone else who has their floors epoxy coated and has not had any issues. So maybe there is a difference in material used that will not burn or spot?
It was suggested to me if you were going to use your garage as a work shop to just used a concrete sealer. It will not beautify your garage floor, but will keep if from staining and it is cheap compared to epoxy. The idea is to keep any grease & oil from soaking in and staining the concrete. The down side is you need to re-apply every year or so depending on usage. Was told all you do is pour it on the floor and use a paint roller on a broom handle to roll it around, so it shouldn't be to hard to re-apply and it drys clear. I have yet to do any of this, so I cant give you any real world experience if the concrete sealer works as well.
