Beaches on the Atlantic are sort of touch and go, as far as water clarity and nice sand. It really depends upon the direction of the coastline and how close you are to sand being deposited, or washed away as the case may be.
The keys didn’t do all that much for me, but it’s an individual thing. The people who love the keys really love the keys.
Gulf beaches struck me as too flat, too hot, shallow water with very little in the way of waves compared to the Atlantic. But, many of them have blindingly white sand and very clear water. Preference, again. A beach without waves roaring in the backdrop isn’t a beach at all, to me. It’s more like a lake. Many like that, though.
I went to the Keys during March a few years back and it was trending towards hot. I was told by locals you have to be insane to go there in the summer. Key West is brutal then and NO breezes.