I would like to share my experience. Recently I purchased Canon Legria HFS10 1920x1080i 25fps(50i) camera and CS4 Production Premium. After some testing I burned 2 projects from our holidays. Fantastic result. Then for some reason a new and important holiday result was as if interlace problem. I tried every setting available but result was the same. Almost ready to blame software I was reading a post that setting should be progressive. I exported all my new projects with Media Encoder H.264 HDTV 1080P 25 high quality. This gave me progressive file and output MP4. Big mistake. Not only that Encore need to convert again to upper fields but quality was even worse as a result. In the end I have found that original recording from the camera was the problem and camera is now being repaired. In my tests at different export settings for Bluray disc H264 codec upper fields will give good result and Mpeg2 will be quick to transcode but with some loss in quality. Progressive should be avoided.