SuSE Linux Enterprise Server (latest is 11.1 / 2) is the best choice for ur demand. It has a very good integrity, security system, maintenance, and needless to say cost-effective os. It has so many features that helps to do no of administrative jobs without hackle. SuSE has a wonderful tool YAST that helps to do not only hardware troubleshooting also does communicate, software installation, updation and patch implementation. To compare with RHEL, SLES is the best server. And regarding RHEL NO THANKS.