When assessing pros and cons, I think it is important to clarify the market for which one is representing. Developers looking for a cost-effective solution to help them with the steep part of their planned hockey-stick growth curve will weigh heavily the cons already listed. For a small business owner, however, GAE is a God-send. These folks most often are looking to "the cloud" as a means to more effectively run their business (i.e. sell physical product and services). For the SMB, GAE the pros already listed can be much more valuable compared to the hockey-stick seeking dev, whilst the cons weight in at a fraction of the devs' measure. I don't see the GAE team doing anything related to SMB positioning, so I guess answers like this are me just pulling on Superman's cape, and spitting into the wind. Really GAE should be absolutely ruling the SMB space now. If not (I have no insights re: user base), then its is a greatly lamentable failure.
