The architecture limitations exist b/c App Engine essentially scales effortlessly once you abide by them.
If you insist on using SQL, then use a company like Heroku, but realize that if your app gets popular you will be paying Heroku a lot of money for the same level of performance you could get for a few bucks a month using app engine.
After I wrote my first toy app a few years ago, App Engine doesn't really feel like it has any significant limitations other than the absence of naked domains and SSL. The recent reliability problems have been a nightmare, but as of Nov 6, I feel like they have been resolved.
I should add that I love app engine and use it whenever I don't need naked domains or SSL. (SSL is only available via .appspot.com domains)
If you insist on using SQL, then use a company like Heroku, but realize that if your app gets popular you will be paying Heroku a lot of money for the same level of performance you could get for a few bucks a month using app engine.
After I wrote my first toy app a few years ago, App Engine doesn't really feel like it has any significant limitations other than the absence of naked domains and SSL. The recent reliability problems have been a nightmare, but as of Nov 6, I feel like they have been resolved.
I should add that I love app engine and use it whenever I don't need naked domains or SSL. (SSL is only available via .appspot.com domains)