I tried html5 on youtube for a week while scaling is nice (the video size increases for window/resolution size), the quality is very poor the same video with same 480p in flash much clear. Though I don't like flash because it crashes many times it is the only way to watch clear 360p or 480p video. Also flash detects 480p as default for my 8 mb internet connection whereas HTML5 will choose 240p now and then. Also you tube menu (choose xxxP or annotation on/off) is inverted L for any thing with sub menus whereas flash is strait oneclick. The other the lightswitch plugin does not work properly with html5 . so I will flash stays as it is only way for me to watch good quality video.