I used u-coat-it epoxy and am very happy. I followed the directions to a tee, scrubbed the crap out of it and etched it. I used grit in the clear, no slip issues here. I did it almost 4 years ago and have found it very durable.
Like Matt said, "...on any epoxy floor (professional or not), you MUST cover the floor beneath your welding...the splatter and sparks will burn and discolor it.".
That floor made my garage much easier to clean up, much easier to find stuff I drop on the floor and made the garage much brighter.