Kamidori is a good game, just not if you're looking for an epic plot or romance. The characters are okay, if not steroptypical, there are plenty of H-scenes if you're into that, and the difficulty isn't too bad. All in all, it's light and easy-going game for the most part.
Also on the topic of Grisaia, I loved the Commmon Route, but when the character routes started and all those twists come out like,
It just made me lose interest. Sure, the game doesn't hide that the girls are in the school becasue they can't really be in normal society, but still, geez.