I redid my Lenovo T520 into a Ubuntu 14.04 machine. A few observations:

The pros: 1. Super fast boot 2. Super fast just about everything 3. Awesome command line 4. great for development

Cons: 1. Battery life sucks on Linux. No optimizations of any kind. In windows, I was able to work for 3+ hours on my battery, now I am happy if I get 1 hour on Linux.

2. Nvidia drivers are still a pain. I tried the built in Ubuntu driver and got super slow refresh rates on a dual 24" setup. On the other hand, the native Nvidia drivers freeze the machine every now and then. Guess I'll just have to live with it

3. Docking the machine sometimes screws up the resolution. Boot the machine undocked, and then dock it seems to be the trick. Not sure if other systems have this issue.