Re: 4 hours playback... See my explanation about how Creative arrived at their playback times vs. how Apple arrived at theirs. If you want to listen to 64kbps WMA files, and watch 500kbps MPEG4 video, go right ahead. You could get the same result on your iPod listening to 64kbps AAC files and watching 500kbps MPEG4 video.
Re: double the songs... again, see my explanation about how Creative arrived at their 15,000 number vs. how Apple arrived at their 7,500 number (hint: 64kbps WMA files vs. 128kbps AAC files)
Re: more audio formats... yes. the Vision:M adds the ability to play WMA files (the iPod can play MP3 and WAV files)
Re: more video formats... yes. The Vision:M adds the ability to play MPEG1/2, WMV9, Motion-JPEG, and XviD.
Re: FM radio, recorder, voice recorder, yes. Points to Vision:M.
Re: iPod's batter turning red with 2 hours left to go... the battery meter is an
estimate, nothing more. If it really bothers you and you can't ignore it, put a piece of black electrical tape over it. My battery meter is fairly accurate, but I've ran my iPod completely dead and charged it up completely 2x since I've bought it. Seems to have helped.
Re: scratching issue.. seems like there were a few people on those engadget posts that were complaining about their Zen (non-vision:M) scratching up pretty bad. My guess is the Vision:M will have the same problems (but that's a guess).
So, summary... If you need a FM radio/recorder, or a voice recorder, or don't want to transcode video you already have in a supported Vision:M format, or have your audio in WMA format, and are willing to deal with the extra width and cost, then the Vision:M might be for you. Be aware that Creative's battery life numbers are even more unapplicable to real-world use than Apple's are (I don't know of anyone that listens to 64kbps music anymore, and who would encode their video at 500kbps MPEG4?).