The great part about riding is how 2 different people can have completely different experiences in the same area. It's what makes the world go 'round.
I love the Pinellas Trail. I've ridden it for years but I'm by no means one of those guys flying by on a really nice bike and who looks like 'a bicyclyst'. I'm the guy riding in regular shorts and a tshirt.
To be sure, there aren't really nice water stations setup on the trail. I've never even heard of places with something like that. That's pretty cool. However, there is water readily available at a lot of parks and there are more than a couple water fountains along the way. Has some kid licked one somewhere? Dunno, never thought about it. It hasn't killed me yet so I guess I'll keep not worrying about it!
The Trail is great for what it is, a casual recreation trail. If you are above a casual cyclist, you may have an experience similar to michelinmike above. I suspect that he's the exception rather than the rule. This does not mean he's wrong in his opinion at all though. Just like I'm a power-user of photography equipment and I won't be satisfied with a point-and-shoot camera that most others would be thrilled with. It doesn't make me right or wrong, just that I want something different out of my experience.
Most of all though, just ride and enjoy.
As to the VERY old request for bike rentals in St Pete - I suspect you long ago got what you needed but I'll second the suggestion of Bicycle Outfitters in Seminole. By the way, they are also right on the trail and have water!
Bingo