Learning how to program a loop is a total waste of time which brings zero value to the end user. If I can hand that drudgery off to someone else, I'll be adding features and stealing your customers while you're giddy about nesting your loops.
Learning how to use photoshop is a total waste of time which brings zero value to the end user. If I can hand that drudgery off to someone else, I'll be adding features and stealing your customers while you're giddy about reducing your PNGs.
We set up on Rackspace Cloud in a couple of hours, and we're running just fine. We're lucky in that our core market doesn't give us traffic spikes.
If and when we run into scaling problems, we'll have a learning experience but that's the same whether you're on App Engine, Amazon or just a cheap web-host running PHP/cPanel/MySQL for £20/year.
GAE is not perfect but it's a much faster environment to develop on than IaaS services like EC2. I spend 100% of my time developing features and 0% of my time developing infrastructure. "DevOps" isn't even a job description in my present company.
It is true that there are occasionally some components (eg large memory indexes) that need to be "outsourced" to other parts of the cloud. It's trivial to do, but we judge each very carefully because of the added operational load.