[TimT]

Check to see that you wont have a problem from moisture coming up through the slab..

Tape a piece of clear plastic to the the floor... maybe a 2 foot square of plastic using duct tape..Check the plastic after a day and see if any moisture is visible..

If you see alot of condensation, you would be better with a stain...

Excess moisture will cause the epoxy to bubble and delaminate..

I live quite close to the ocean and bays and estuaries... ground water is only a few feet beneath the ground here.... unless a barrier is placed under a slab here, most garage floors don't do well with epoxy coatings (here)