ubuntu or RedHat which better?

Yes, it is obvious that you like Ubuntu, it is easily configurable and has an excellent user interface. Redhat Linux is also an excellent Linux distribution however it is not free (that's where the problem begins!), however it is the most popular Linux Distribution as far as the enterprise sector is concerned. Also, Redhat Linux is the only Linux distribution with which i have been able to achieve best connectivity to the internet, be it broadband or the dialup connection. In fact i even succeeded in configuring a winmodem with Redhat. Whereas, with all other Linux distro's i had a great deal of problem setting up the Internet (in fact i had to use static ip address and network configuration tool to manually tweak my internet connection). So, Redhat is pretty good!. I found Ubuntu Dapper Drake a bit to heavy on system resources, so i gave up and settled for Open Suse Linux a much better Linux distribution.