My organization is using RHEV which is a RedHat supported version of the Apache Licensed oVirt. Video.linux.com has videos teaching the use of the system including an introduction to oVirt architecture. RedHat also has ePub versions of 12 documents including their REST API documentation, which looks very promising for CLI and automation tasks. It has a nice GUI if you can stand IE; Firefox support is coming and the IE requirement is just a remnant of the company they bought to get RHEV, from whom they then released the source. A windows server is no longer required (just Tomcat and PostgreSQL). If you really can't stand a Windows VM you can go all CLI; just accept that behind the scenes it will be passing XML to the server and back.
We're still using Dell servers but are considering Cisco UCS. UCS attracted me because it offers flexibilities that standard servers don't seem to have, in particular the ability the manage physical machines like virtual machines. For example, automatically flash any subset of the servers with a variety of properties including: version x of the firmware, the mac address of the previous server running it so the OS can't tell the difference after a hardware upgrade, and to store and apply machines profiles like software. Also, we already have full Cisco network gear and the cabling for it is much simpler with just two 40G uplinks for a full chassis. Like the XIV and RHEV, it has a platform independent GUI as well as a CLI which is all based on the same XML API. With all of Cisco's talk of vmWare you might think they didn't know RHEV existed but RHEV is fully supported and tested by Cisco. UCS also has plugins for RHEV to integrate management. I can imagine using the similar API in a single script to orchestrate events on my SAN, Server, and Cluster manager and it seems attractive.
Below are some slides from a joint presentation from RedHat and Cisco on RHEV and UCS:
