After learning the basics of web development using GAE, I've since moved on to other platforms like RoR and NodeJS. But GAE still holds a special place in my heart.
Many of our students tell us Steve's udacity course was their first run-in with web development.
GAE may allow you to set up a server visible to the entire Internet, but I think my fonder memories will be reserved for other tools.
What I specifically liked is the fact that they introduced and discussed concepts that I won't necessarily deal with unless I happen to be working on a high traffic app or site, which at this stage of my life (Senior student living in a developing country) is unlikely to happen. Thank you Udacity.