I have very very limited experience with EC2, a single small instance, for over a month, but I think that gives me more credibility when I say this, don't use EC2 unless you designed your whole app to run on servers you expect to catch fire and explode at any time, because my single little instance died within a month, then twice it, well, did something I've never seen happen before, blow out a device driver? So I couldn't ssh in, all I got was "PTY allocation request failed on channel 0", so now I'm on my fourth instance. I couldn't imagine the carnage if I had been running tens or hundreds of instances.