I did my last two floors with Groit's floor epoxy. Once about 12 years ago in Seattle, Washington and my most recent (9 year old floor) in San Mateo, California.
The only mistake I made in Seattle was not to put any sand or non-skid material in the epoxy. It was slippery, especially after parking our everyday driver in the garage, water dripping onto the floor, well you get the picture. It was just plain dumb not to do it.
My current floor has been down for 9 years plus and it is holding up very well. I prepared the floor by having a company come in and shot blast the surface. That was a mistake because the blasting took too much of the top layer of concrete and created what they call "corn rows" of surface grooves. The reason I went with the blasting is because I used a concrete additive that prevents water penetration. I thought I needed more adhesion, which I'm now okay with because the several coats of epoxy filled the corn rows fairly well. I've dropped wrenches and tools on the floor with only minor chipping. Since I don't really drive a wet car into the garage, I didn't use any grit on the entire floor, I like the smooth feel when walking over it. However, I did broadcast some clean fine sand lightly at the door entries about 4 feet inside. After the sanding, I applied the final coat. It turned out great and today is still very nice, no slipping, none. Haven't heard many other reports about the epoxy that Griot's sells, but I will attest that it is fairly easy to apply (follow directions), prep the floors properly, allow to dry/cure and enjoy. I like the floor without the flakes, looks more like a dealership service area.
But that's just me.
But I do enjoy looking at all the pretty things people do on here.