Heroku's Advantages Over Google App Engine
Pros:- Postgres (you can even use pgAdmin to view your database)
- Uses Git to push your application into production
- More monitoring features and 3rd party apps
- As long as your project uses one dyno, it runs for free (similar to google, but with a less confusing billing structure)
Cons:
- 10k row limit for your database before they start charging you $9 per month