I recently switched to a X1C6, and I wholly agree. It's an amazing laptop in terms of hardware and build quality, but it does have a bunch of Linux compatibility problems.
The trackpad didn't work out of the box, I had to change some settings; annoying, but no big deal. What's a bigger problem is that the trackpad buttons don't work after suspending/hibernating, and I still haven't been able to fix that. Also, the fingerprint reader and NFC do not have any drivers on Linux.
The Arch wiki page[1] has been tremendously helpful in getting set up. However, I think the length of the article goes some way toward showing that compatibility is far from perfect.
The trackpad / NFC issues seem to only be present on laptops with NFC behind the trackpad, so my recommendation would be to avoid that one if it's possible to get a similar model without.