I'm not a spoken-word poet or slam poet, but I sure like hearing them when they're good. If you'd like, you can read a few of my thoughts about spoken-word poetry here. To appreciate such poetry, I think it helps to have some of the following: some urban experience or sensibilities (not necessarily a minority---i.e. Taylor Mali---but at least some guts to get up on stage and let it sling), something bothering you (be it racism, the state of the union, annoying drivers, class wars, etc.), and a former or current love of punk, folk, or hip-hop, tattoos and/or good books like this, this, and/or maybe this.
The spoken word poets I like write great poems, so I am able to love them (i.e. read them again and again, have to take a breath after certain powerful lines, sounds, and images, etc.) without ever hearing their voice. Then, sure, the reading can enhance it. I don't know a lot about the spoken-word scene, but I know there are some good ones here in Fresno (Anthony A. and the guy who read the hurricane poem at the fundraiser I organized, and the always awesome Devoya Mayo) and I really like Saul Williams, Bryonn Bain, Sam Pierstorff, and of course the unbelievable Ishle Yi Park.
But I'm writing this to encourage you to check out Bao Phi and Ed Bok Lee, two poets I've admired for a while now. I'm newer to Ed's poems, though I really like them. I love that they write about real things---race, love, connections and disconnections---and that they don't rely on some of the basic wit that I think weighs down so many poems of this genre.
If you read this good article on the two of them, you can find out about their backgrounds, what they're up to now, and visit their websites for sample poems, book and booking info, and more. Spread the word.