What cloud hosting to choose for a project on Ruby on Rails?

If you consider cloud hosting for Ruby On Rails application, what should I choose?


Criteria:

1) I Want to be able to run multiple sites in one configuration (if I understand correctly, on heroku.com impossible). It's not a critical item.

2) I Want avtomatizirovannye (autoscaling)

3) I Want built-in support Rails (although not necessarily), and rails 3

4) I Want cheaper :)


If you have experience deploying rails applications in the cloud, the request to share impressions