Personally I actually prefer the IBM X1 Carbons, they have the nicest keyboard I've ever seen and a good keyboard is IMHO a must for a coder hacking keyboard.
Thinkpads X1s look really nice. Why is it better than XPS?
If you do a lot of coding, it's just a better ride than "compressed" keyboards.
13" is a nice form factor, but I find the 14" X1 just has enough space to give a nicer typing experience.
Just my opinion, you should see if you can try one out, and see what you think.
Thinkpads X1s look really nice. Why is it better than XPS?