We chose Quicktime in order to support both PC's and Mac users equally, and to store the replay movies in a file format that would be playable by the largest number of people and video player programs out there, as well as being compatible with YouTube, etc.
For PC users who don't want to go through Apple's install process, please note that Quicktime Alternative
works for TF replays, and can be configured to install only the codecs needed to play and create Quicktime movie files.
That said, we are looking into providing support for additional video containers and video codecs in the future. Obviously I can't promise anything concrete, but I think our track record of ongoing support for TF speaks for itself.
Remember, we just released the Replay feature *one day* ago.
We're going to watch closely and listen to you for problems to fix and ideas for future development.