Nice and simple
I've been looking for something like this for ages! There are other video feedback apps out there, but his one is unique in that it plays back sound. This is perfect for intense musical instrument practice sessions, where one can truly listen and attend posture, intonation, etc. of one's performance with the distance and objectivity of the recording, without having to do complicated setups. The automatic mode is great, keeps you focused on the runs, and gives a rhythm to the practice session. The developers seem to be very active on its development -- polishing and adding features very quickly. The "don't show myself as I record" feature is also very useful so you don't cheat on your posture because you're seeing yourself as you record. It turns off the playback while you're performing so that you get the surprise of your stance, the faces you make, etc.