In general, posts are a little more SEO friendly than a web page but both have value. Pages are for static content like your About and Contact pages which have long term value for content. Posts are much more timely and can be put in categories with dates and tags. When you publish a post, it is linked within your categories, tags, archives, and recent posts, and other multiple-post page. You can feature posts in different widgets on multiple pages which helps with SEO throughout your site.