The benefit of WFRP over EotE is that there are special abilities (actions) to the characters beyond talents and it's in a Fantasy Setting.
I like the obligations of EotE and I'd like to see that adapted for WFRP by some ambitious fan here.
I wouldn't really say that Fantasy is a benefit over EotE (unless you prefer Fantasy of Sci-fi, ofcourse), but it is a welcome change from all the blasters and spaceships. I'm an overall fan of the custom dice system that FFG has created, and I both like Warhammer and SW... so it's a win-win for me. The only (small) downside to both systems, for me at least, is that I only know a little about both universes. It takes some time to research the world you're playing in, whereas you can create an entire world out of thin air for a game like DnD. Ofcourse, one might argue that you can just drop the Warhammer lore and create your own, but I prefer my games to stay as close as possible to the established lore.
The main attraction to WFRP for me, are the components of the game (and its dice system, ofcourse). It's what makes the game unique, in my opinion. I know that the game has received a lot of flak for this, but I consider it one of it's selling points. Naturally, I can only confirm this after having played a game myself.
Also, I'm not really a fan of Obligation in EotE, so I've decided to drop it (I only used it to limit my payers during character creation and to help them come up with some kind of background). Obligation is something that seems to happen in any RPG, FFG just gave it a name in EotE.
By the way, do any of the adventure supplements come with additional rules, options and/or extra lore? Or are they just that: premade adventures?