The experience of listening to an author read a poem immensely different from reading one on a page. There is some poetry that first came truly alive for me because I heard it read by the poet. Charles Wright's work is one example. Some years ago, I heard him read "Clear Night," and it changed his work for me; I can hear his voice when I read him on the page, and it made him far more accessible for me.
A good reading always reminds me that poetry is meant to be spoken, and it's one of the few public spaces where you can hear an entire audience share a small, inspired, satisfied exhale--that sound you hear again and again at the end of effectively read poems. (If I had time, I would go around and record that sound at readings and turn it into an audio collage. It's a sound you hear nowhere else.)
There are also cases, I think, where poets' readings--due to nervous public speaking habits such as speed-reading or a pompous, bombastic manner--can threaten access to their work. The few times I've done public readings, speed-reading due to sheer terror was something I had to fight through. And I've had this distancing happen with at least one of my own favorite writers; when I first heard her read in person, her peculiar manner and cadence was so difficult for me to get past that I resolved never to see her read again. (A note to poets: For god's sake, practice before you read your work publically. Don't become the literary equivalent of these guys, butchering brilliant material.)
But I digress; generally, hearing a writer read their own material is almost always a good, enriching experience. I would not want to pick between the experience of a poem on the page and that of a poem out loud, but the latter has become increasingly precious to me due to its rarity in my life. I read poetry all the time, but don't go to readings as often as I'd like.
I'm posting these because I only recently became aware of their availability: I think Nick Flynn (author of the hilariously named memoir Another Bullshit Night in Suck City and, more recently, a memoir that delves into the subject of torture) wrote one of the most amazing poems of the past decade with "fire." It's terrific on the page but stunning out loud. You can listen to it at the audio link here.
And this whole reading is worth the time, but at 56:18, the amazing Tony Hoagland introduces and reads an amazing, moving poem about shopping--a rare thing indeed.