(I just watched the _TV series_, so the below comments are in regard to the TV series only. I'm not talking about the OVAs/movies/manga; would have to refresh my memory on those first. But, you guys are free to take the discussion down that route, if you wish.)
So, on the negative side, it got kind of repetitive. I mean, how many times do we see Kyosuke and Madoka get close, just to get interrupted at the last moment. There wasn't particularly any suspense for me in that regard. And, talking about repetition, how many times do we see Kyosuke make Hikaru go off crying, just to have them make up before the end of the episode? (The Umao and Ushiko gag was repetitive, but I loved it every time.

I mentioned this in another thread, but the fact that Madoka can do basically anything and everything gets kind of annoying after awhile. This isn't to say that anime has to be realistic; oh no, of course not. It's just the way that Madoka can be a female wrestler in one episode and an expert skateboarder in the next that kind of gets on my nerves. But again, as I mentioned in another thread, this girl that can do everything may actually be weak inside.
The TV series ending doesn't particularly resolve the love triangle. Are Kyosuke and Madoka finally together? What about poor Hikaru? For all we know, she could just pop up unexpectedly, interrupt Kyosuke and Madoka, and set us back to square one.
But, on the other hand, with all that, jeez, this show is addicting. I just can't put my finger on what it is about KOR that is so enchanting... Can you? (or do you not think that KOR is enchanting?)
Your thoughts on KOR?