One very unique idea you can see here is that logs are always grouped by request. In all other tools I have encountered, Kibana for instance, you will only get the log lines that match your search. By always showing all other log lines around the one that matches your search, it gives you more context. I find this extremely helpful when investigating issues in the logs since it immediately helps you to better understand what happened. I truly miss that feature in every other log viewer I use.
Another interesting trait of the App Engine is that each HTTP request is automatically assigned a request ID. It is added to the incoming HTTP request and uniquely identifies it. This can come in handy to correlate a request with its logs. For example, we were sending emails when an uncaught exception occurred and included the request ID - this made it trivial to look up the logs. The same can be done for frontend error tracking.
Version 2.4¶ (codename Correlation, released on April 13th 2010) * the environment template loading functions now transparently pass through a template object if it was passed to it. This makes it possible to import or extend from a template object that was passed to the template. * added a ModuleLoader that can load templates from precompiled sources. The environment now features a method to compile the templates from a configured loader into a zip file or folder.
If it is a small project then it may not be the best choice, (ie a simple project a few models, 1 or 2 handlers, then something like webapp is probably the most appropriate). If it is a lot larger, many models, possibly multiple views per entity with out an explosion of handlers, need for arbitrary depth urls (graph traversal) and/or mixed with traditional routes. security models beyond basic authentication.