I have a 2 car garage, the former owner was a plumber and did a lot of pre-cut pipe for jobs in this garage. Needless to say the floor was both chipped, cracked, and oil soaked. I spent a LOT OF MONEY to get the oil & chips out. Even went as far as to rent a concrete grinder to prep for an epoxy finish. After all that work, seems the oil had permeated the concrete, and there's not an epoxy company that would guarantee I wouldn't have problems with summertime, hot, sticky, performance tires pulling up the epoxy from lack of bond. Considered the plastic tiles, but after seeing (and hearing) them in other peoples homes, then reading about how some people are finding mold from trapped moisture under them, I banished that idea.
In my quest for alternative flooring I discovered some tile mastic that would bond to the now rough surface. Finding a tile warehouse, I offered to take any 500 sq. feet of porcelain tile they couldn't get rid of. Surprisingly, they had TONS of the stuff. I picked up 16 inch square tiles VERY cheap, and contracted with a local guy to put it in. He even cut pieces for a 6 inch base around the walls so hose down cleaning is a snap.
Unless you're going for a Dealer Showroom Floor look, just get a good strong tile in a neutral color. Stay away from 'clay' tiles, and 'thin' ceramic tiles. Porcelain tiles are very strong and have not let me down. Ask the installer to install them as tightly as possible and use the 'largest cut trowel' when applying the mastic as that's the base for the load on the tile and will prevent cracking under heavy loads. After the grouts cured, get a good grout sealer and apply liberally several times a year. This will keep the grout from staining.
OH ... you'll have to test for moisture coming through the concrete. Securely Duct Tape all sided of a 5 X 5 piece of plastic to the concrete floor, one edge against an outside wall. Leave there for one week. If you pull it up and there’s moisture on the plastic you can’t epoxy or tile the floor as the moisture will shortly erode any bonding. I’m luck I’m at the top of a hill & have good drainage.
Hope you do too. Good luck.