The XPS's keyboard would multi press, the touchpad didn't work great, the hinge made it difficult top open the screen, the speakers kinda sucked. Don't get me wrong, it was a nice laptop, but felt very over hyped. A death by a thousand cuts. I felt a bit let down from what I expected after reading a bunch of reviews.
On the other hand, when I finally got the the X1C, I couldn't believe that there was so little hype about this laptop. All I would ever see online is stuff about macbooks and the XPS line, nothing about the X1C.
The X1 is such a solid machine. The interface is completely uncompromised, yet it is so light, it feels like I've just got a spiral bound notebook in my bag when I'm carrying it around. Feels like a leap ahead, rather than two steps forward, one step back.