It is the game that made my players start thinking before actions.  They have a lot of fun and enjoy sessions.  
WFRP core, Old World Bestiary, Warhammer Companion, & Sigmar's Heirs
are the key books to me, followed by Skaven book, Realms of Sorcery & Old World Armoury.  Border Kingdoms is interesting and I hope to be picking up the Vampire book this weekend. 
D&D is a clean fantasy for the most part, while death and wounds are there, death does not hold fear to the players.  WFRP is a darker game, you just don't worry about death but also taxes.  An orc in warhammer is going to kick you butt for a hell of a long time, it is 50/50 on who may win, that is a single green skin.  Oh, sickness and illness are nasty and common in WFRP.   
I have seen where people have issues with careers but that is minor, you can get around it just by having advances but there is no fun in that.   

  I also have my players tell me how they get together, I don't tell them, I just start the game.