While we are worried that performance may be lower and costs higher - we are not sure if this would be the case. If we can get the same performance for a comparable cost (say within 10 to 15%) of what we are currently paying, we would prefer EC2 for two reasons 1) Redundancy - in case we have a problem it would be easy to restore instances and be back up online quickly 2) Flexibility - as we occasionally (2 or 3 times a year) do have peak traffic loads when we could use more servers.