I haven't heard much from Eminem. Lil' Wayne -- I've heard him too often.
Both have two totally different styles. Neither; I would say. I like Eminem for his old material because it made sense (which is why most people like him) , but he's tucking his head under the sand. I'm not sure what else he could rap about. He's a white rapper -- hooray. I'm white. Who cares anymore? He could perhaps, feature in another's song. But another album himself? Eh.
Lil' Wayne, I don't even know. He needs to take a break. I'm beginning to think he's overrated.
But, to each his own.
In all honesty, most SHOULD like Eminem because of his meaningful lyrics - that also run at a fast pace, with a nice beat. Which, frankly, isn't all too easy. Any rapper can write lyrics that make SENSE, but it doesn't have to sound good. A lot of them focus on the beats, and make them memoriable. That's why some lyrics are s**t but the beat is so amazing.
J. Cole; Mr. Nice Watch, for instance. Wonderful beat. Lyrics, hey.