We went out jet skiing in Key West in 2004. Found the more shallow areas to be very clear. But when we were out in deeper water it was harder to see----but a very pretty blue-green color. This was during the month of November.....not sure if the water is different during different seasons. I've never been to Clearwater, so I can't compare the two.
it has greenish cast to it inshore, but generally is more clear than say, Clearwater. (does that make sense?) visibilty depends on different factors. I've seen the water so clear off Clearwater you could see the fish around a wreck site in 70 feet of water.