My opinion of this manga seems to change every time I read it. Sometimes I really enjoy it and sometimes I hate it. I'm not going to rate it because I honestly don't know what to give it...
Let's make something clear: Nobody in this manga is even remotely normal. At first I thought that Medaka was the only weirdo but as the manga goes on sometimes I wonder if she's actually the most normal. I mean, she may be inhumanly perfect in every way but at least she reacts to things in a sensible way considering her abilities. Everyone else in the manga seems like a caricature.
The thing is, none of the problems they deal with in this series are actually exotic or extraordinary. They tackle normal issues that normal high school students might really encounter. But all the characters in this manga are all so exaggerated that they blow everything out of proportion until it seems extraordinary.
Case in point: The money-obsessed swim team. Sure, there are lot's of people in real life who are obsessed with money, but few of them are so jaded that they will proudly proclaim to anyone who might be listening that money is really the only thing that matters to them. But what I really can't get over is...if they are so obsessed with money why did they form a swim team? They don't appear to care about swimming at all. Why didn't they get jobs or start a business or something? It just doesn't make sense and the author never provides a good explanation.
It's all boke with no tsukkomi. Sometimes that can work but other times it just seems...surreal. Like watching some sort of weird play. It makes me wonder if this story is even set in Japan or if it's set in some alternate reality that just happens to bear some resemblence to Japan.
It doesn't help that there doesn't seem to be much in the way of story progression. The series is stuck in the same repeating pattern. And the current story arc (student council vs. enforcers) is the most surreal yet. I feel like I will drop it from my reading list soon if it doesn't go somewhere...
OK, enough with the negatives. There is a reason I have kept with it for this long: It actually can be quite funny at times. You just have to turn off the part of your brain that is worried about why the characters act the way that they do and go with the flow.
Edit: Well, that was unexpected. In my original comment I criticized this manga for (among other things) its lack of direction. I said the story didn't appear to be going anywhere...well, now it's going somewhere: straight to mediocracy. Seriously, this setup was never suitable for a shounen battle manga but that appears to be what they want to do with it. Blah, I have just lost any interest I had in this series...