I believe I've made this comment before - Google App Engine is good and quickly allows you to get a proof of concept off the ground. But the documentation SUCKs big time - the language is obtuse, the documentation is repeated in multiple places (meaning different paths to documentation explaining the same thing in different ways), and it is not uncommon to find that the documentation is not current.
The google cloud documentation is definitely sub-par. I tried to build a simple Go app trying to use the pubsub api and eventually gave up. None of the documentation provided a full working example and any example you can find references an old version of the api. And this was with Go!
> What's missing from this fluff piece is the top 5 reasons why its better than AWS.
AWS and AppEngine aren't even the same kind of thing. AWS is a high-level collection of services (Google's equivalent is Google Cloud Platform.)
AppEngine is a PaaS offering within Google Cloud Platform. And, AFAIK, its one piece of GCP that AWS doesn't have a direct competitor to. (Lambda is, I think, the closest thing.)