How is Key Anime seen in the Anime community?

I've just started watching anime this year and I've been watching ones that are pretty well known, and that reasonably short (less than 2 seasons).

Some of the anime I really enjoyed were Key Animes including Air, Kanon, Clannad (and After Story), Angel Beats and Little Busters.

Some I'm curious to how Key Anime is viewed in the anime world.

For example, is it seen as:
Too mainstream?
Too emotional?
Awful?
Really good?

Like I've said I'm new to anime and I'm just curious what well rounded and veteran anime fans think of Key. BE HONEST !