Those are not “Ubuntu Web Browsers”. And give Konqueror a try.
I felt the need to clarify some things with this article that discusses so-called “Ubuntu Web Browsers”. The fact of the matter is that those browsers are in no way tied to Ubuntu. Likewise, Ubuntu supports browsers other than those.
Browsers like Firefox and Opera run on many different operating systems, from Windows, to Linux, to Mac OS X, to Solaris, to FreeBSD. Check out the Opera FTP site for proof of this. Look at the wide range of platforms they support. And don’t forget that some of those directories, like the “unix” directory, themselves contain several platforms.
As for the rendering problems you mentioned, you may want to give Konqueror a try. It’s a browser put out by the KDE project, and should be quite easily installed on your Ubuntu system. It uses the KHTML rendering engine, which is different from the engines used by Opera, Firefox, and the other browsers you mentioned.