I had a X61, I think that was shortly after Lenovo started building them and still very much like the models before. But that was a long long time ago.

I’ve had good ones and meh ones. In terms of build quality, the X1 Carbon gen3 I got ages ago was outstanding in most respects (including how easy it is to get the back off), but the memory is unfortunately soldered and the CPU is decidedly mid-field, and it was a refurb so I couldn’t really up-spec it. The T14 gen2 (AMD) I got a couple years ago and use as a personal dev machine these days has WAY better hardware (Ryzen7 5850U; 16g soldered + 16g SODIMM), but the build quality is not as nice and the back is WAY more of a pain to get off (fucking plastic clip sections).

I’ve had no real issues with either in terms of Linux compatibility; I’ve installed various distros on both of them, but generally have settled on to Ubuntu or Fedora for long periods. The old X1 is back to windows now though, simply because I am repairing and modifying a car with an OBD-II port, and it’s way simpler to use pretty much any automotive diagnostic software from a windows platform, and I wasn’t using it for anything else.

Edit: also my old IBM T60p from college - iirc one of the last ones they made before Lenovo bought them. Bloody thing just refuses to die lol