it's like saying your favorite point gaurd is Steve Francis even though you know Iverson is better. MCing has technicalities and I believe that it's some opinion and some fact when it comes to picking "the best MC." of course there is always your own preference (i.e. i like Stevie Franchise's game better than AI, but AI puts up the better numbers). you may like the way Black Thought flows better than Nas becuz it just sounds more natural to your ear, but you still know Nas' overall lyrics are better than Black Thought. so IMO, it's possible to have an MC that is your favorite and an MC that you feel is "the best." I personally love AZ but i'll be the first to tell you that Nas is better becuz his lyrics are more complete, his beats are better...etc etc. it just so happens I like AZ's flow and relate to a lot that he says.