What I'm loving about Konqueror is that when I press the stop button, it stops downloading immediately so I can move on to what I actually wanted. Both Firefox and IE take quite some time to actually stop downloading, it seems they try to finish whatever files were already downloading when the stop button was pressed. If those files were large then the only way to move on is to close the browser and start again. Javascript is a major pain for both as the stop button has no affect on javascript scripted downloads, you can press the stop button a thousand times and the javascript will just keep on downloading stuff you do not want.
A functional stop button is critical, Konqueror's works, when I press stop it stops, so I can then move on to load another page.
One of the simplest features of a browser, but one of the most important for me.
It is available for windows (
http://windows.kde.org/) but it is still alpha and needs more work. Hopefully it will be finished soon and I can enjoy Konqueror in windows too.