1 - It duplicate the video frame, so the end-user need to broke the link everytime to remove the secound video.
2 - If your video URL came with any variable info inside it like: "feature=player_embedded&" it simply dont work, and again, you need to teach your client how to manually remove this peace of information from URL.
I hope you fix it, and I will be glad to give you 5 star review. It can be the best... IT CAN, it is not yet.