I have a Thinkpad x201 and switched the built-in Intel wifi chip in favor of a Qualcomm Atheros AR9285 which works just perfect. I got the Atheros off Ebay for ~3.50€.
The whole process was a bit of a mess but manageable thanks do Lenovo's whitelist anti-feature. I wrote it all down, sadly it's only in German but at least the commands or some automated translation service should help: http://vinzv.de/wie-man-den-wlan-chipsatz-in-einem-thinkpad-x201-austauscht/ vinz.
