[bmh_ca]

FWIW, my personal anecdote: I chose Google App Engine for a large enterprise application almost a decade ago and it's been absolutely, undeniably one of the best choices we made.

The application is locked into Google, but that hasn't proven a problem yet and can be designed around if need be.

[StavrosK]

My personal anecdote is the exact opposite of yours. I picked GAE for one of my personal projects years ago and it has been terrible. You can't do certain kinds of lookups unless you build the indexes first, there are no delete cascades, no intra-table constraints, etc.

I suspect the difference between us is that you spent the time working around these problems, whereas I expected it to just work.