I've done all combos before and unless you either prep your floor meticulously or have a new concrete floor or have it done professionally, the off-the-shelf epoxy doesn't work that great in the long run. I've seen commercial stuff last quite awhile with lots of abuse though. Once again, it's all in the preparation.
Over the years, I've used garage paint, Rustoleum epoxy, Quickrete, race-deck, , rubber squares, commercial tile. I've personally found commercial tile to be the best for my application.
There are a few determing factors and it's really dependent on your envrionment and application.
If you do light work, you can get by with the regular consumer epoxy. But you should do the moisture test first.
Moisture Test: duct tape a 2'x2' square plastic film to the floor and see if it collects any moisture from underneath. If it does, there's a good chance your epoxy will lift over time.
Also depends on usage, like if you weld, use heavy hoist and equipment, etc.
Speckles are just for grip but if you don't like the look, you can substitute sand in it's place.
You'll want to use Muriatic acid at the least to prep your concrete floor if it's not new.
My $.02