Application Insights
If you are running your Sitefinity site on Azure you might as well be taking advantage of Application Insights to record and analyse performance. By default, Sitefinity logs everything to a text file. Annoyingly you can't read this because the file is locked by the app. You need to wait until it starts a new file the following day. You can push all these events to Elmah which is supported out of the box. But with Sitefinity's extension model you can write your own class to push out this information to your own logging source.