From my experience AWS is one of the most reliable hosting providers. It's extremely easy to setup a fault tolerant infrastructure using cloudformation, puppet/chef etc, boto and a bit of autoscaling. The only disadvantage AWS has is costs. In many cases it's more expensive than a traditional hosting provider. On the flip side, your engineers will be more productive.

What I miss in this article is any details on why they had issues with AWS. You can't just say it wasn't reliable and not explain the details. AWS works for all of the world's largest startups, why didn't it work for Swiftype?