I am still using my X201s as my daily driver. Lovely keyboard and Decent resolution (the 220 has less pixel density I believe) All the hardware works flawlessly under linux ( In my case Fedora, KDE desktop) the trackapd is fine, I never use the stick as it irritates my RSI something rotten
About the only things I have done over the years is max out the ram (8G) and add a decent SSD
I regularly run KVM guests (various server builds), windows guests under Vmware workstation, use it as a netboot server for building servers, etc. A real all-purpose workshorse
think-wiki is a great resource for these machines http://www.thinkwiki.org/wiki/Category:X201s
Also bear in mind that the docking stations are often available for cheap and these (+ a spare PSU) are really nice for desk use with a bigger monitor etc.
I am a little nervous about trading up for fear they may have 'improved' some of the hardware I really like.. But honestly I don't feel the need ye as the x201s still capably meets my needs.
I also now have a work provided entroware Apollo and it's my go to machine for business travel these days (long battery live, lovely bright pixel dense screen with great resolution, fast)
Again hardware that works flawlessly and as a bonus was put together TO run linux by people who care. However I am not very fond of it's keyboard, I guess the X201 has me spoiled in that regard.