Lets hope they've fixed the problems
The graphs auto-sizing has been a disaster. If you happen to view too many graphs, rather than provide a scroll bar, all the graphs resize themselves so small that you can't see them... in an effort to all stay in the same window. I've been stuck on the flash version thanks to this... and that's even come with its own problem in the latest Firefox in that nothing can be typed in the input boxes until you click off the browser and then back on it again.
I really am bitting my nails over migration to HTML5, and I hope they've made it usable for people whose monitors aren't necessarily the same size as VMWares.