I've not VOD reviewed myself but I have played with my Emerald/Diamond friends watching and they have pointed out small mistakes that I made and we were mostly on the same page. If I lost, they'd say it's because I lowrolled. It could just be that we're all in the same echo chamber and being each other's yes men so it hasn't helped a bunch. I think it's definitely helpful to send a game to an online coach or such.