I'm a fan of harem anime, and since I heard about Bakemonogatari I immediately assumed I was going to love it. After I'd begun watching it, though, it was so utterly boring I wasn't able to get passed the first 5 episodes. I struggled through, hoping it would get better, but I eventually had to drop it.
I might come back to it some day in hopes of giving it another chance (because I really do want it to be good) but in short, it's a very slow paced and dialogue-filled and monotone anime that seems more like a shoujo.
If you enjoy ridiculously slow, slice-of-life style anime, like perhaps School Days, you would probably enjoy this. Otherwise, don't waste your time.