I've converted several boats to diamond plate floors, and it's the high end upgrade on custom made aluminum boats built around here, it's my favorite floor for a fishing boat.
1. It is shiny when new, after a short time it will become dull, you can speed the process up in several ways.
2. It doesn't get that warm, it's not that much different than most other surfaces.
3. It's a one time and done surface, it will never need to be replaced, although putting it over plywood may limit the life of the substructure. We try to put an alumnum framework under it.
4. It's not slippery, at least after it's dull. We did spill some oily bait scent on a new floor one time and it was a bit slick for part of that trip.
5. Bikinis are not fond of aluminum, so this may influence your decision.
6. If you live in FL it may not be the best choice, we don't fish barefoot much in this part of the world so how it feels on your feet isn't that important. Other products may be much better in this environment.
7. Carpet and vinyl are way down the list, I know some people love vinyl, but it's the lowest end flooring product used on boats, and it doesn't hold up that well to hard core use. Carpet isn't even a possiblity on a fishing boat for me.