I'm sure I'd like Immortal Technique if I listened to him more, but I've never really been all too impressed with what I've heard. Content-wise he's knowledgeable and opinionated, but I feel like that's a prerequisite of being a decent rapper anyway. To craft wordplay and intricate rhyme requires a type of a technical skill and matching those with appropriate allusions and wordplay requires one to be knowledgeable.
I don't really get into "Who's the best?" arguments because the criteria are all over the place. I don't mind the self-referential rap if it's clever, which is why I can appreciate some Wayne. I go crazy for heartfelt lyrics though. Blu's "Cold Hearted" just makes me feel something indescribable. The politically conscious like Dead Prez and P.O.S. is well-appreciated also. And what about sheer rhyming ability? The first few bars of Abdominal's "Vicious Battle Raps" have absurdly intricate, multisyllabic rhyme.
To the person that said nerds don't typically appreciate hip hop, I agree. I don't think the typical nerd would go into, but what's typical? Ignoring Nerdcore despite my appreciation for Front and Optimus Rhyme, what are you left with it? It's expected that they will buy into a genre almost exclusively about their interests and experiences. How many of those same folks are listening to hip hop at large? I would say a small percentage. First and foremost, I appreciate many of the nerdcore artists (especially Front) for the different in style: the vocabulary, the irony, and the unique samples. After that I laugh at the jokes about video games and computers.
[/words]
[obligatory: tl;dr]