Heroku my feels cheaper when you think about how long you can punt on having ops proper person(s) & how much time you save rolling your own everything.

My experience of Heroku has mostly been the pain of migrating to a different platform once you grow to the point that their pricing (and abstraction) starts to act against your growth.

Heroku is great for general applications, but if you're trying to do something that isn't a standard CRUD app, it can really start to bite you in the arse.

Their DB pricing in particular is incredibly inflexible compared to AWS RDS. Among other issues we had with Heroku at my old job, was having a DB that was hitting its storage limits, but was miles away from hitting its memory or connection limits. There was no option but to upgrade to the next tier, with additional memory etc., even though all we needed was additional disk.

That's not to say that Heroku is bad, but like any tool, you need to be aware of the long term costs that are often associated with term convenience.

If you don't mind my asking, can you say why you moved from GAE to Heroku and/or why you prefer Heroku over GAE?

I used them both in the same time period. I liked GAE because it was basically free to use for low use web apps, but has scalability built in. I liked Heroku because it was just so easy to develop and deploy with.