I dunno. It depends what parts you use. I find the S3 interface is painfully slow so I end up using either command line or GUI tools. On the other hand, I don't mind the interface for EC2. If you are doing big EMR jobs, however, you need automation to avoid blowing $15 on a bum cluster.
One thing I do know is that there are parts of the AWS console that look similar but that have differences of the sort that make me think the implementations are different.