For a platform to provide scaling, it pretty much has to provide proprietary services if those services are to scale as well. AWS proves this point, with their

For a platform to provide scaling, it pretty much has to provide proprietary services if those services are to scale as well. AWS proves this point, with their proprietary elastic block store, elasticache, SQS, SMS, etc). I don't know Azure at all, but I'd be very surprised if it's scalable services weren't proprietary too. So I hold that it is the scaling that locks you into GAE, but only to the extent that you desire scaling. Scaling gives you redundancy and reliability too, don't forget. > GAE -> easy to get in...very hard to get out! If your codebase is really 70% datastore API calls, I'd strongly suggest writing your own wrapper so you can change datastore by updating a few primitives. But in any case, GAE is no harder to get out of than any other scalable platform. > and expensive... We run three services with millions of users, for about 250 USD per month. Given a single dedicated server starts at $75 USD per month, and that we'd need at least four servers for redundancy and scaling, and that we'd need to hire a system architect/administrator for say ten hours a month to maintain them, I think GAE is excellent value. > and risky... You don't say why you think GAE is risky. In terms of uptime, our experience is that it is an order of magnitude more reliable than AWS or Azure. The other risk people sometimes suggest is that Google will discontinue the platform, but Google seems strongly committed to Appengine and Appengine has a three year deprecation policy for any part of the service. > it's not worth it We obviously disagree on this point. I would accept "it's not worth it if you will never need scaling and are happy to do your own system admin for free".