I've stuck to ThinkPads. They are great....or were great. They recently changed the keyboard (bad) and also got rid of the physical mouse buttons (NOOOOOO! BAD LENOVO!).
With those gone, there isn't anything particularly compelling about the current ThinkPads. In that case, just pick most anything and go with it. Ubuntu should run great on most anything these days.
Are you aware that you can install a Linux distribution on just about any hardware? System76 are OK, I've never been wowed by them. Realistically, I would just go with a Thinkpad, unbeatable keyboard and great build quality (though lately Lenovo has been messing up on both of those)
Yes, I am aware of that. I am talking about things just working out of the box. It depends on which linux distro you use. I am not talking about just installing linux here.
There are choices - Fedora, Ubuntu, Mint, OpenSuse etc. and each distribution differs in user interface and the hardware support (graphic cards/wifi/bluetooth etc.). So far, Ubuntu seems to have a slight upper hand on hardware compatibility.
I just bought an x1 carbon and loaded it with ubuntu. Just about everything worked out of the box, less microphone mute button and sleep button. It's pretty flawless and hands down the fastest machine I've owned. Battery life is also awesome (5-6 hours).
ThinkPads have a historically good reputation because kernel developers tend to use them. But as trouserpants says, almost all of the machines from major manufacturers will work fine.
I'm sorry, but this just does not agree with my experience. Yes, if you work at it, you can probably get 80-90% of things on your machine to work. But even getting to that point takes some effort. And quite often, there is that 20-10% that just doesn't work quite right. Like not being able to wake from sleep reliably. Or having popping noises when you play audio. Or having some of the audio jacks not work. And it just frustrates me to see this kind of blithe assurance: "Oh, don't worry, everything will work."
It's the same story with distributions. So often, someone asks what the best one is, and several people say something like "They're all good---you can't go wrong!". Which, again, doesn't agree with my experience. There's always something janky no matter what distro you choose. But the good ones (like Ubuntu pre-Unity) had considerably less jankiness.
I wish we lived in a world where you could install any Linux distro on any random hardware and have everything just work. But that is not the world we currently live in.
If you want some 100% no issues working, just get something with Intel CPu and GPU. Although the free Radeon drivers are pretty good now too. Avoid some kind of integrated GPU+extra discrete chip combination. Otherwise there isn't really anything special to worry about or to buy a special "built for Linux" machine (which I consider marketing bullshit).
Honestly, I just install it and don't pay much attention to the brand of the machine. The issues I have had installing an OS seem to be about even whether I am installing Windows or Ubuntu.
The only issue I had with my Toshiba Satellite P855-S5312 was getting around secure boot, which is easier now. I've been running Ubuntu on it for about 15 months with no issues.
With those gone, there isn't anything particularly compelling about the current ThinkPads. In that case, just pick most anything and go with it. Ubuntu should run great on most anything these days.