In August of 2000 I moved into my "new" house and shop. Before I moved anything in, I thought I should take advantage of the opportunity to paint the floor. I think a grey painted shop floor looks professional, and it has practical advantages in that it reflects light and makes it very easy to spot dropped parts. The only thing on the floor that isn't the same color is the nut or bolt you just dropped.
There are many brands of floor paint, but because I've had good luck with other Griot's products, I decided to use their epoxy floor paint.
It's been over 4 years and it still looks great, with a few exceptions. The spot where I had to drag giant metal shelving a few inches (too close to the wall to keep it on the dolly) across the floor has no paint. I made such deep gouges that I think I actually pulled up some concrete. Obviously no floor paint can survive having the concrete carved out from under it. There's another spot where it's coming up a bit, but I still remember there being a bunch of oil stains there. I apparently didn't get them cleaned up as well as I thought I did. You'd think that just the acid etch and pressure wash would have been enough, but I guess some oil had soaked into the concrete in places. Another mistake I made was not going back and doing a third coat in some spots where I laid it on pretty thin because I had no experience painting such a huge surface area (1400+ sq ft) and getting an even coat. Years later I can still sort of see through to the concrete in those spots.
Another strange thing I didn't expect was that some combination of the acid wash and the paint made my floor bumpy. I didn't notice it until I was applying paint, but most likely when the acid etch removed a tiny layer of concrete, it left behind the reinforcing fibers, some of which must have been pointing straight up. I'm glad it did that, since one of the dangers of a painted floor is that it's slippery to walk on, especially if you spill anything on it. I got a little texture in my floor by accident. If you're hoping for a museum style shiny finish rather than a floor you can use to work on cars, you should plan for how you'll avoid this.