The new Dell XPS 13 Developer Edition is a good looking and well-built machine. It doesn’t come with Windows installed (if that’s important to you), and it runs Ubuntu and Fedora virtually perfectly. It’s a great machine for developers and system administrators.
I’ve been looking at the XPS 13 as a replacement for my ageing ThinkPad X220. I managed to get my hands on an XPS 13 (for a few minutes) a week ago and it looked like a really nice machine — the screen was very impressive. My only concern with regards to purchasing one of these would be the build quality, I’ve been using ThinkPad devices for a number of years and they have always been rock solid. Whereas, my only experience of Dell machines has been at work, and I’ve not been overly impressed with them. That said, I guess the XPS 13 is a premium model, so I’d expect it to be higher quality than the Vostro models.