Hewlett-Packard

I currently have four HP-UX machines. HP and HP-UX feel very "business-like" when
interacting with them, similar to how IBM machines feel.
HP-UX's system administration tool, SAM, is well-designed and feels complete. In later
versions of HP-UX, they transitioned from Motif GUI applications to a web-based
management tool called SMH, which has a similar look and feel to iLO interfaces. I
haven't spent much time with the later HP-UX versions yet, but I plan to experiment with
HP 9000 containers and Integrity VM.
Of course, I'll also keep an OpenVMS 8.4 installation on my Integrity machine. One day, I hope to build a VMS cluster with x86-64, Itanium, Alpha, and VAX (if it's supported).