A few years back I would have probably written off Sun Microsystems for dead in the water. The company I worked for in 1997 was a big Sun shop and I was fortunate enough to see Scott McNealy speak at the 1997 Netscape Developers Conference. Over the years though, I think the company just didn't keep up with the rest of the world and they went down hill. With Jonathan Schwartz now at the helm I think they may just turn it around.
First it was environment friendly servers, then open source Java, Blade Servers, Black Boxes and now the Sun Refresh Service. It is basically insurance to make sure you can do upgrades in the near future that will hopefully let you keep up on the efficiencies they offer while upgrading performance as well. Everyone else is doing a subscription-based service, why not hardware vendors? Anyway, it's an interesting thing to check out.
Here is the link directly to Sun and here is an article that the Data Center Journal has on the Blade Server speed record and Refresh service.