Hey George, I'm sure the devs will be happy to hear your positive comments :) I just wanted to suggest that, if it is the first time you are using pitivi 0.13.3, to take a quick look at the user manual (I wrote it). Namely, there are two issues you may encounter with rendering (with workarounds), which are detailed in the "troubleshooting" section of the manual. One of them is not crackling in the rendered audio, so I thought this might be quite important for you to know.