Why use the OpenSolaris OS you ask? It’s pretty simple, you’ll find it full of unique features like the new Image Packaging System (IPS), ZFS as the default filesystem, DTrace enabled packages for extreme observability and performance tuning, and many many more. We think you’ll be quite happy you came by to take a look!
And, I found ths headline interesting enough to actually click through to the article: OpenSolaris: What Ubuntu wants to be when it grows up. http://blogs.zdnet.com/BTL/?p=8703
I was recently checking out OpenSolaris to use as our central disk/file server as it supposedly has excellent iSCSI support. And, of course, ZFS would be pretty nice to have for a storage server as well.