I think comparing me to slicehost or linode is completely fair... they are my direct competition. I think ec2 is in a different market. there is some overlap, but really if you want to leave your instance on all the time, a vps such as I sell (or linode or slicehost) is vastly superior to the instance with unmirrored disk ec2 provides you.

the opposite is true as well; if you need instant provisioning... if you need 50 servers during the day and 20 at night, I simply can't do that for you. (I hope to be able to at some point, but I can't yet.) Ec2 has been doing that for some time, and I think slicehost and linode both have similar functionality.