We built http://www.schoolbookings.net on Appengine. Over a thousand schools and half a million parents use it - not enormous numbers, but a very real and profitable business.
We pay under a hundred dollars a month for extremely reliable and scalable infrastructure. I'm happy that our platform is designed and supported by the best sysadmins in the world - we've had less than five minutes of degraded service (high latency but still accessible) in the last six months. I'm soooooooooo glad we didn't choose AWS!
Appengine is perfect for developer-centric startups. You can concentrate on your app instead of the infrastructure until you've got traction, and if you do hit the big time you'll be popping champagne corks instead of server cores. At that stage you'll be able to make an informed decision about hiring some kick-ass sysadmins to build your own platform, and migration really isn't as big a deal as some people make out. Python apps are WSGI compliant so will run with minimal modification on any WSGI server, and you can access all your data without difficulty. You would need to write some wrappers around API calls, but this isn't a huge deal and realistically you're going to have to do this for any platform migration.
We pay under a hundred dollars a month for extremely reliable and scalable infrastructure. I'm happy that our platform is designed and supported by the best sysadmins in the world - we've had less than five minutes of degraded service (high latency but still accessible) in the last six months. I'm soooooooooo glad we didn't choose AWS!
Appengine is perfect for developer-centric startups. You can concentrate on your app instead of the infrastructure until you've got traction, and if you do hit the big time you'll be popping champagne corks instead of server cores. At that stage you'll be able to make an informed decision about hiring some kick-ass sysadmins to build your own platform, and migration really isn't as big a deal as some people make out. Python apps are WSGI compliant so will run with minimal modification on any WSGI server, and you can access all your data without difficulty. You would need to write some wrappers around API calls, but this isn't a huge deal and realistically you're going to have to do this for any platform migration.