Curious if the epoxy those of you have used is expensive? I know of a guy that had his done by someone and it was thousands of dollars for his shop. It's about 60' X 30' I would guess.
Not cheap anyway you look at it, but in addition to materials cost
older floors will probably need a lot more prep (degrease, acid wash, abraded surface, fill gouges,prime coat) ie - labor = $$$
