I was using IE7 in WindowsXP and as people have already mentioned it was nothing but a little bit fancier version of IE6 with tabbed browsing and kinda buggy as it seemed to have conflicts with the previous version of IE in my computer. But right now I am running Vista RC2 and as IE7 is the default browser, I am very much surprised by the smoothness of it. Granted, it looks like the browser which managed to copy few things from Firefox and other from Opera but it works good. Anti phising, parental control, popup blockers and the RSS feed reader are the new things here. Overall I have no problems with IE7.