What are some alternatives?
When comparing AWS and Rackspace, you can also consider the following products
DigitalOcean - Simplifying cloud hosting. Deploy an SSD cloud server in 55 seconds.
Microsoft Azure - Windows Azure and SQL Azure enable you to build, host and scale applications in Microsoft datacenters.
000webhost - Zero cost website hosting with PHP, MySQL, Cpanel & no ads!
Heroku - Agile deployment platform for Ruby, Node.js, Clojure, Java, Python, and Scala. Setup takes only minutes and deploys are instant through git. Leave tedious server maintenance to Heroku and focus on your code.
HelioHost - Community powered free hosting for everyone.
Linode - We make it simple to develop, deploy, and scale cloud infrastructure at the best price-to-performance ratio in the market.