Personally, I dislike the Silverlight version.... but that's only because I'm using a computer that I built on a budget three or four years ago. The older version worked fine on it, but this new version is just too much for my pitiful rig (1.34 GHz, 768 megs of RAM). Note that this is a personal complaint - it sucks, but I don't expect companies to cater to old hardware forever.
With that said, it works like a dream on my wife's computer (which isn't bleeding edge hardware, but it's very powerful), and I can't say anything negative about the quality or the overall performance on it.
I wonder how many of the protesters are in my boat (low-end hardware, maybe better than mine, but still not up to snuff) and just don't put two and two together.