I've not played very much Fantasy at all, but the few games that I did play made me stop in exasperation. It's an infantry block game now to such an extent that you need 40 plus models in your rank and file core units to have a chance of doing well. I just don't have that many models (for my Empire army at any rate, I can just about do it with my Vampire Counts force), and without those kind of formations, I just don't see how you can win without a significant slice of luck, or if your opponent makes some tactical errors.
Cavalry, in particular, really don't get a good deal in the current edition of Fantasy, so if, like me, you like mounted units, you'll be disappointed. Other units are a mixed bag, depending on the army, and special rules which they benefit from.
The rules are also more complicated in my opinion, and involve too many minutiae, a bit like how 40K is going (you'll find a number of similarities).
That's about as much as I can say, since I'm not well versed in how strong any of the armies apart from my own are at the moment, and I'm disinclined to play any more games, since the ones I did play weren't enjoyable for me.