Every chapter is a stand-alone game. That means a whole new story, continent, 50+ PvE missions, new PvP/PvE mechanics, new professions, monsters, armors, items etc...
This is from the official FAQ @
http://eu.guildwars.com/support/article/factions_faq/What kind of new content will I find in Guild Wars Factions?
* A total of 300 new skills, including 90 new elite skills, for the two new Factions professions and the six core professions from Guild Wars
* More than 50 new locales, including story missions, combat arenas, and questing areas
* More than 100 new creatures
* New guild halls
* New faces, hair styles, and armor sets for both Factions and the core professions
* New pets
* Hundreds of new weapons and items
And that's not even mentioning new Faction Alliance Battles and new PvE/PvP game mechanics (Cooperative, Challenge, Elite missions).
So yeah - it's definitly worth €40.
This comment was edited on Apr 19, 01:52.