A few more reviews on HP's new MediaSmart Servers that you might be interested in reading, the first two are from Windows Home Server MVPS, Alex Kuretz and Donavon West.
Review: HP MediaSmart Server EX487
Hewlett Packard Announces Two New MediaSmart Servers
HP's MediaSmart Server: Second Time's the Charm
HP Makes MediaSmart Mac Friendly
HP Unveils Mac Compatible Home Media Server
Tech Power Up
HP Launches New MediaSmart Home Server for PCs and Macs