Of the first two-day jaunt, this was probably the most stunning all-around. I don't know if words really work to describe how it shined in the morning; the pictures below do it much better justice.
The park is technically a state park but is maintained by the SRWMD, so there's no visible staff or complex facilities; this probably went a long way to preserving some of the fun of the park. The spring has a direct-access jumping platform and a dock; paths are made of mud and roots, not concrete; there are no ropes to be found in the swimming area. The spring run snakes around a small limestone formation and into the Withlacoochee river, crashing over a line of rocks into the tannic water.
This spring has everything: cave diving, free diving, deep swimming, shallow areas, wading areas, relaxing rapids, river wading, and fishing. My only regret is not swimming. We were in a hurry and it was the first spring of the day, but I do very much regret it. Madison Blue Springs State Park is highly recommended, and I cannot wait to go back someday.
This one gave me the creepiest vibe of all I visited that week of the vacation, mainly because it A) was down a set of railroad tracks, B) was about to rain, C) had very distorted limestone formations, and D) had many places to fall into the run. Literally, the path down to the shore was slanted at about 30-degrees, and the slope went down into a hole in the limestone, right into the dark run.
It is definitely a site to see; the formations and the way things have generally fallen apart/been built up are spectacularly unique in the Florida springs world. It's scary, it's wild, it's strange, and that's enough to warrant a visit.
I downgraded my opinion of this spring to a "minor" spring mainly due to the difficulty of access (legally) and the danger of the area. I've read on the net that the spring is a popular diving/scuba destination, but the thought of that is almost too much.
It was later in the day when I first visited Manatee Springs, so that probably already threw off the trip a little. The park was moderately busy but the swimming area wasn't very crowded. With only one entrance to the spring pool area it was a little congested getting into the water, but once afloat there was plenty of room to move around.
It's worth nothing that there's almost nowhere to stand in the pool. As far as I could tell, the water pours out of a cave between 30ft and 40ft below the surface. You can swim to the banks near the cypress trees and barely get your toes on the sand, but for the most part this is a snorkeling and floaty spring only.
Diving down to the cave caught me by surprise as I had to clear my ears three times before getting to the mouth, and even then the force of the water escaping pushed me a good five feet downstream. This free-dive isn't for the feint of heart and could be the deepest I've had to dive to find one (save maybe DeLeon). It's enough to make me want to go back in the morning when the water is clearer and the sun is higher.
When they say covered in duckweed, they aren't kidding. There were nice boardwalks leading down to the motionless spring, and there were... odd noises coming from under the duckweed, but nothing really to see or do for the average sightseer or swimmer.