A lot of them are pretty meh, but I found this one to be pretty neat. It's actually a three level dungeon, about 30 rooms.
At some point though, I think the one page dungeon format gets in the way of being effective. So much information is crammed into such a tiny space that a) it's hard to read and b) just seems pointless, just sticking to a format for the sake of being a gimmick.
Anyway, despite the drawbacks of the format, it's nice adventure. The author is apparently French so there are some oddities in the text, but nothing too bad.