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.