The image in HTML5 took much longer to load and loaded in pieces, leaving lots of "blank areas" while the sections of the spherical image loaded, while the Flash version loaded completely with blurred areas progressively loading.
Also the HTML5 version has lines between the sections of the image that shift around.
Also HTML5 doesn't autoplay all the images like the Flash version does
Simply speacking, Flash has far more functionality than HTML5 currently does
I'm using Firefox on XP