We've been using EC2 for a while now, before most of these plugins were available for Heroku. We're extremely comfortable with the platform and our tools for managing it.
We have most of our customer-facing nodes on m1.large instances since we have a lot of caching (mostly loading all of the data in memory) up front and then the rest is CPU bound.
Scaling Heroku is nice since it's just some knobs you turn, but Chef isn't that much more difficult and it's just a different type of knob.
We've been using EC2 for a while now, before most of these plugins were available for Heroku. We're extremely comfortable with the platform and our tools for managing it.
We have most of our customer-facing nodes on m1.large instances since we have a lot of caching (mostly loading all of the data in memory) up front and then the rest is CPU bound.
Scaling Heroku is nice since it's just some knobs you turn, but Chef isn't that much more difficult and it's just a different type of knob.