First, does it run the warhammer world well? Are the rules well suited to the setting? Not especially. In the same term they're not exactly badly suited, but there is not many reasons that this system would model the old world particularly over other settings. I mean I quite like the system, but it is not exactly tailored to the game.
This being said, it does do a couple of things for the setting in particular. It does keep the career system from other versions of wfrp. I don't think it could call itself wfrp if the game didn't have the iconic career system. It also has a system that helps make the magic seen dangerous, and sometimes the characters get a random problem from the deck of miscasts. This makes the magic very chaotic, which is true to the feel.
It also has mook rules for combat. Now, in general, I love me some mook rules. I GM a lot more than I play, and the idea of having to sit and slog through char gen for a bunch of goons who the players are going to tear through on the way to the big boss generally makes me sad. But, well, is the warhammer world, with it's usual rat-catchers desperately thwarting cults vibe the right place for these rules? I mean, they are optional, so i guess they are good for running Gotrek and Felix. But less the band of doomed idiots trying to not get the plague and freaking out when they see their first skaven.
So,to sum up:
Things it does well:
1) The NPCs stats come on little cards. Pick some cards for their abilities. That little stack? NPC generated. That's a total length of time of about 60 seconds. When you have been running a game that made you generate too many characters for every NPC this comes as a godsend.
2) The characters abilities being on cards and the tokens. I know I went on about this last time, but it is a revelation for management of information.
3) The party card is a great idea. Stuff that gives a benefit to the whole party, and a brief description of the party on it? Yes please. Loves this idea.
Things it does badly:
1) Dear god the healing system. They revised it in the second publishing, but the system is still a mess. I think, after 3 years of playing and running I understand it now, but I could not swear to it.
2) Balance. Some types of casters are just better than others. Though to be fair, it is the most common types who get the most love. Priest of Sigmar getting a better power set than priest of Ranald, probably since one is much more common tan the other.
3) Mandated xp spends. You have to spend xp in certain amounts to finish a career. Your career may only have space for 2 talents, and you may have the two you want, but if this is your third career, you are buying another talent to sit and look useless in your character box. This irrationally pisses me off. I hated spending an xp I knew I would never ever get use out of.
Things I would steal for other games:
1) the cards. I am in the process of writing a system for a more crunchy fate. It incvolves putting stunts on cards and turning them to see when they are ready to be used. Basically because I stole it wholesale.
2) The party sheet. I like the idea of players being able to share some powers with the whole group if they put it on a party sheet. Would use in other games with a very distinct party.
That is two things, which as my reviews continue, you will see is 1-2 more things than most systems manage! So, my end rating?