No, I truly meant it. Everything related to the datastore is difficult and tedious. Goodbye to incremental development, goodbye to knocking out a feature in an hour. Every single change you make has to be planned.
Adding a field to an "object"? Where do you use that object? Is there somewhere that you don't use that field which becomes too slow?
How are you going to migrate that new field? There aren't tools to help you migrate. Generally, you have to change to an Explando, add the field, load every single object from the datastore, then save every object back to the datastore.
These are two examples off the top of my head. Every change you want to make in App Engine has similar questions raised. I really did mean it when I wouldn't recommend it to anyone.
I think it's a much different learning curve than with any other technology. I'm plenty adept at learning new things, but this was just unnecessary complex, with nothing to redeem it.
