I agree that the cloud can make the best case for hacking side projects. It's quick to deploy and quick to destroy. However, scaling your system depends on ho

I agree that the cloud can make the best case for hacking side projects. It's quick to deploy and quick to destroy. However, scaling your system depends on how you architect the system. Building in the cloud is not the same as building in your colo cabinet. Your example of moving your instance to a bigger one is a classic example of doing it wrong (so to speak). In the cloud you don't scale up, you scale out; many machines doing the work. And bringing those machines on-line takes minutes, that is certainly faster than shutting down and rebuilding. I've played with EngineYard & Heroku and while I really like their services, they tend to re-enforce the "old world" way of doing something. Break out and play with "raw" AWS and I think you'll find a lot to like.