I think that no matter what, Free! is a really fun anime to watch. It's only 12 episodes, so of course, there is nothing to compare with other anime that is actually based of a manga, since Free! is based off of a light novel. Considering the fact that Free! wasn't even supposed to be an anime, it's held up pretty well.
I started watching Free! very impressed with how well written it was even with the excessive fanservice. I think that the way they animate the water is really beautiful. You can really feel the motivation behind the characters' thoughts. The storyline starts out filled with tension and I think that most people will want to continue watching to see what happens. Overall though, I don't think the overall plot is anything very revolutionary, and does very much fall into the slice of life genre with maybe more angst.
I think that later on, the plot does get a little lazy however, which is why I stopped taking it as seriously and just started watching casually to see what happens. The reason that the plot falls flat I think, is because the characters that have been so carefully developed are then used in the later episodes in these really melodramatic ways that made me cringe. For example, the way that some expressions were animated took away from what the anime was trying to communicate.
Also adding to the silliness of the later episodes was the ridiculous soundtrack...there were moments where the music was just ???? completely inappropriate and laughable. Normally, I am fine with whatever music but even to my ears, there was just too much of a disconnect.
Overall, though, I think that in the end I probably just expected too much of this anime from watching the first 3 or so episodes, since I hadn't read the light novel. If you watch the series just expecting something a little fun, I think you would like this. The characters are even pretty amusing sometimes!
