I'm using 3.5 and had no problem at all. But keep in mind I don't visit flash enabled or useless web 2.0 junk sites. gmail does loads faster as compare to older 3.x version. There is also porn mode aka private browsing. This is useful for net banking. However, it did screwed up non-English websites. For e.g. newspaper website published in a local language does not renders correctly .. may be it is font issue but it worked with older version. Oh and it does support HTML 5 and CSS 3 open standard. You can watch those videos without flash plugin. I really home adobe flash dies out one day and html5 becomes reality. Oh and all my addons worked - ABP, Zotero, no script, firebug, Y speed, the web developer, stumble upon and google toolbar et all.
HTH