Most garage floor conversations start with a product name and end with a shrug. The two names homeowners hear most — epoxy and polyaspartic — are usually presented as rivals. In practice they are two halves of the same floor.
Epoxy is the workhorse. It is a two-part resin that bonds hard to prepared concrete, builds film thickness, and carries the color, the flake, or the metallic pigment. Polyaspartic is the fast, light-stable relative. It cures considerably quicker than standard epoxy and holds its color better under ultraviolet light, which is why it so often serves as the clear topcoat over an epoxy base.
So the honest answer to "which one" is usually both, in the same system, each doing what it is better at. A floor with an epoxy build coat and a polyaspartic topcoat gets the thickness and color of one, and the speed and UV stability of the other.
Where the difference bites in South Florida is moisture. Concrete is not dry the way a board is dry. It holds water and moves it, and a slab-on-grade across Broward and Miami-Dade sits over soil that stays wet much of the year. Coating a slab means trapping a surface that naturally wants to give moisture up. If water is still driving its way out when the resin goes down, the coating can blister, cloud, or let go — not because the product was wrong, but because the slab underneath it was never read properly.
That is why prep matters more than the label on the bucket. Grinding or shot blasting opens the concrete so the resin can key into it mechanically. Cracks, pits and spalling get repaired first. Moisture gets tested before anyone mixes a batch, because the reading decides which system is even appropriate for that floor.
Humidity in the air matters too, though less than the moisture in the slab. Coatings want a temperature and humidity range during application and cure, and a Florida summer pushes against the top of it. That is one more reason polyaspartic earns its place here: it sets within hours rather than days, which keeps a weather window usable, though full cure still runs longer.
If you are comparing systems for a space, our services overview sets out each one and what it is built for. The practical version: ask what the system is, not which product wins.