I just received my new camcorder, a Canon Vixia HF R400, and need some guidance on which format to use. This camera can shoot in either MP4 or AVCHD. I currently have iMovie '09 on my computer; in order to upgrade to iMovie '11 I would have to upgrade my OS from Lion to Maverick (which would lead to a whole other set of questions!). I have 2 primary uses for the camera: 1. Record my son's sporting events. I would then edit the videos into highlight clips, and would like to be able to burn them to CD's, and more importantly, post them to websites such as YouTube. 2. Create short video clips to either post on YouTube or on my personal website. My questions: 1. What format would you recommend I record in, which would allow me to accomplish the above? 2. In a previous thread I started, the general consensus was to upgrade to iMovie '11; would it be worth it to upgrade my OS primarily for this purpose? If the general process of video editing from an image quality perspective, compatibility standpoint, ease of use, and being able to use the better format (m4 vs AVCHD) indicates that FCP is the better option, I have no objections to purchasing it. The only other issue is the amount of memory available on my mid-2007 iMac (if either format or "software" uses less "space"). Any and all advice/guidance would be greatly appreciated!!!