Both have their pros and cons. Netflix typically has a larger streaming library, and they also starting to have a good library of their own 'netflix tv series'. Amazon has a smaller library, but it also has things that Netflix does not. Amazon also has other content available to stream. Also, Amazon Prime let's you get 2 day shipping for free on a lot of their products.
Personally, I'd suggest giving each a try. I believe Amazon Prime has a 30 day trial, I don't remember if Netflix still has a free trial option or not.
