We've had a very different experience than you. We've used Appengine since 2009, and are about to launch our third service built on it. It's important to under

We've had a very different experience than you. We've used Appengine since 2009, and are about to launch our third service built on it. It's important to understand that that Appengine is not AWS. It is a massively distributed system providing scalability and fault-tolerance that you would need something like ten AWS servers spread over several availability zones to replicate. Slow - true, request responses can be several times slower than a single AWS server. That latency is due to the distributed nature of the datastore and memcache - but that buys completely seamless scaling. So if you think you need speed to handle lots of requests, you don't. Appengine will spin up as many instances as you need to manage your traffic. Expensive - I'm a nasty mean bugger so if there was a cheaper option, I'd take it. A single server on AWS might be slightly cheaper, but ten AWS servers spread over several availability zones (and the sysadmin to manage them) are definitely not. OSS - ummm, you haven't read the article, have you? You have access to the source code of pretty much everything. Stable - in the early days of the master-slave datastore, we did have occasional outages. But in the last four years we've had a single outage that affected our customers. I thank my lucky stars every time AWS has a hiccup. Furthermore when there is an outage, I know there are better sysadmins than I could ever afford dealing with it. At the end of the day, it's the usual horses for courses. If you like doing your own sysadmin, Appengine will fill you with horror. But if you are a developer, Appengine abstracts the system admin away so you can concentrate on doing what you do best.