It's not that bad of a diy job. Only takes a couple hours. First time I used the Rust-Oleum kit but added traction grit. No flakes. No clear coat. I wouldn't recommend adding grit since I work on my own cars and sliding around on your back under a car on a gritty surface is no fun. That floor held up for 10yrs in St. George heat with only minimal lifting from tires.
Second floor was done using Sherwin Williams tintable epoxy. Again no flakes (I like to be able to find what I've dropped) and no top coat. Going on 12 years now and still perfect.