What a great job you did on this garage!
I'd say spring for the best 2-part epoxy coating you can find. You get what you pay for, and that includes the prep material too.
About 10 years back I was running a campus auto shop - 75 year old concrete floors (you could see where they filled in the "pit" when the lift was put in). We degreased, washed, and etched the floor, then coated it. The most work was moving out all the equipment. Well, 10 years later that 2-part coating has held up everywhere except where someone dropped slag from the torch. It's been soaked, greased, engines and 5-ton jacks dragged across it. The only thing that could hurt it were those big globs you get when someone doesn't get a clean cut with an oxy-acyt torch. Even then, it just burns a little hole - no flaking. Great stuff, that floor.
And the best thing we did for lighting was cleaned the ceiling and put a fresh coat of white paint. Makes for a lot of non-blinding shadow-free light.