I played Kanojo-tachi no Ryuugi... like most games by that company, the relationships are twisted and incestuous, with a lot of surprising drama despite many of the characters being mostly straightforward.
Iinchou wa Shounin-sezu bored me to death... it was sort-of funny for the first part of the game, but the actual romantic portion is worse than most moege.
H20 is pretty overrated... people kept trying to get me to play it, but I couldn't get into it.