Stock browser, based on Old Webkit2 branch which has not very good plugins support (does not have) Also it very far from certification quality with that branch... but I guess it would not be hard to add that support by hacking: http://gitorious.org/+qtwebkit-webki...it-webkit2-dev ... Firefox/Fennec has pretty much stable plugins-backend support, also it multi-process out of the box, which helps to not kill Browser when flash crashes