both Dell & HP servers are horrible, usually lacking features & poorly configured, one of my client installed 5 HP blade servers it took HPs Techs 2 days to get them installed and then 2 months to get configured as stated in the service agreement and they still dont work correctly.
another small business client had a basic dell server that was setup in a dynamic mirror raid and was backing up all its data to a second partition so when both hard drives failed he had no backup.
I've like Lenovo for large clients, enterprise corporate & government
and Supermicro for small business.