[programminggeek]

Amazon's win is elasticity, moving your servers up and down often. It's not as big of a win if you have a known quantity of resource utilization over a long time period.

Actually, there is a win to be had there too. If you can spin down your instances with load in an intelligent way, you can save A LOT of money using a combination of reserved instances an on demand instances.

However, if you had a program that was smart enough about dealing with load and spinning up/down instances and managing cost relative to reserved instances, on demand instances, and spot instances, that could save a ton of money.

That kind of optimization is tricky so it's a lot easier to just switch providers like the OP.