Ezinearticles will give you better exposure with search engines, but it is a pain in the butt getting your articles accepted. ArticleBase is less strict.
Neither are worth much since the Google Panda update earlier this year. I had many articles in Ezinearticles on page 1 of Google and got thousands of views monthly from them. Not any more. It's almost impossible to get any kind of decent traffic from ANY article directory these days. Put your articles on your own sites and you'll do alot better.
Both ezinearticles and articlesbase are good but given that you can include your affiliate link it is better to go with articlesbase and they have some categories which rank very high in search engines. But articlesbase do not provide dofollow links so if you are looking to get dofollow backlinks then go for ezinarticles.