Georg Zoeller - Designer -
Highier prority: options and ease for fan-developers/DM's OR an awesome Offical Campaign?
I can think of serveral high quality mods and campaigns. Sure, since the toolset is quite-easy-to-use, there'e a good number of not so good or outright bad modules, but I found a good number of very enjoyable and high quality modules.

Just some of the modules I found very enjoyable/memorable (and I'm quite picky, especially when it comes to bad scripting )

Campaigns:
The ShadowLords Series (5)
The DreamCatcher Series (3)
The Lone Wolf Series (2)
The Lord of Blight Series (2)
A Call for Heroes Series (3)

Modules:
The Nether Scrolls by Papermonk
Sex & the Single Adventuress
Witch's Wake I
To their Heir is human
Foreboding in Sylvani
Beerfish's Nature of a Man

All those together were probably several hundreds of hours worth in free modules, and that's only the ones I still remember playing / was able to play.