The key to it, like anything, is in the prep work.
Use muratic acid diluted to clean the concrete. Don't waste your money on any of the namebrand preps or cleaners - they are all mostly re-labeled muratic acid.
I painted a slab at the back of our property with Dutchboy concrete paint after cleaning it twice with diluted muratic acid, and the paint has held up good to winter, lawn chairs, and firepit.
My bro-in-law did his garage floor with epoxy, but his prep work sucked and it was peeling in a year. And he had no texture to it, so it was slick as snot when wet or oily. Sprinkle it with sand or something to give it a little texture/slip resistance if you plan on working out there.
