To throw in one more environment you may want to take a look at flexiscale. It may work out more expensive (largely because they're based in the UK) but they h

To throw in one more environment you may want to take a look at flexiscale. It may work out more expensive (largely because they're based in the UK) but they have some nice features. Persistent storage, F5 load balancing (you don't need additional instances to set them up as with EC2) and automatic restart if something does go wrong with an instance. Again, I haven't used them, just a bit of research.