Linux

For me it's Dell, when I bought my (used) Latitude E5470 there was even Ubuntu running officially on it IIRC at the time. I like the small Dell because there's ton of them 3+ years old, parts available everywhere, they are pretty solid and made for corporate world, they are no toy like Asus. A $1500 model can be had for like $200-300 after a couple of years. I installed MX Linux on it, everything works perfectly without touching or configuring anything.

For instance now you can find a nice E7480 for 200-300$, with Core I7, 8GB or 16GB RAM, SSD, 1080p, NFC, fingerprint, USB-PD dock compatible, etc.

Bought my last few laptops from Tuxedo. Their 13" infinibook can be quite noisy, but I'm having a blast with the Polaris I bought last year.

The X1 Carbon series is popular with Linux kernel devs, so it's had a lot of TLC. It makes a big difference for some stuff like sleeping. My Thinkpads handled sleeping really well, and I could expect to leave it sitting for at least a week and come back to somewhat low battery. My Framework laptops, as nice as they are otherwise, will drain the battery during sleep in 24h, no matter what I've tried. The situation is apparently better on the newer-gen Framework laptops, and IMO Framework's open nature will lead to a similar situation to Thinkpads, but it's not quite there yet.

Apart from sleep, I've heard complaints about the manufacturing quality of some of the other options, but haven't used them myself so can't verify. Might be why some people recommend the Thinkpads, though. I do really like the quality of the Framework, and I'd recommend people take a look at them over Thinkpads now, unless they care about sleep battery usage.

To chime in with some of the other answers, price also makes a difference. Thinkpads have been around long enough that there's a nice large used market. I got a rock-solid Thinkpad T480 for a few hundred dollars from some dude on Craigslist. My Framework is higher-specced and was paid for by my work, but it still starts out ~$800. I think it'll just take time before other manufacturers have a similar situation.

for another (other than Tuxedo) EU based solution: https://slimbook.es/en/
(They are at Valencia, Spain).
But I have no about idea its quality as I have never tried one.

Ease of availability of third party repair/replace parts, and due to economies of scale, them being cheaper as well. Also I know that Lenovo will officially provide me the parts easily even 6-7 years down the line, no matter if I am a business or home/personal owner of a ThinkPad. The only complaints I am seeing are the newest fingerprint readers on selected models like Yoga being less compatible, other than that everything is as standard on Linux as it gets.

Some of these dont really ship worldwide. Not all of them offer a good bang for the buck in terms of hardware specs, and big companies sometimes offer more options (system76 traditionally didnt offer screens over FHD, most laptops are only 14"....).

those manufacturer either have to charge thouthands, or use the cheapest possible hardware they can find to be interesting compared to the thinkpads of old, which can take a punch or two and get replacement parts

People will say many things. But at the end of the day, it’s the keyboard. I honestly cannot think of a company that does keyboards better than Lenovo (formerly IBM).

Not sure, but, I dont think any of them are available outside usa/europe. Lenovo has more global coverage

Had Tuxedo experience: 3/5 at most Had ThinkPad experience: 4/5 at least

Entroware is another you could add to the list. I had a good experience buying from them. They do the usual Clevo OEM things.

Price, used thinkpads are cheap. I know I can get parts basically anywhere too.

One factor is that laptops need a little more design work to build out main boards and validate relative to a desktop, especially considering that you optimizing for power draw and that very little of the design is socketed. As a result a good chunk of the Linux laptop market uses OEM provided designs and then tailors their software around it. Last I heard system76 was working to bring that design work in house.

Framework has some quality problems, not everyone is a fan of the keyboard, and it's relatively expensive.

Tuxedo is quite good, but they often use stock Clevo models and customize them, so they might be cheaper and not that well designed than one by a "proper brand".

Not sure about the rest.

There's very little alternative if you want a ThinkPad style keyboard and track pad/trackpoint for the price of a used or older ThinkPad.

$$$

Also Vant and Slimbook from Spain. I own a PC from Vant and I'm happy with it but I would think twice before buying a laptop for 1.5k when I can just get a used lenovo for half that price and use it for next 10 years.

The first machine I ever installed with a distro was an MSI Ultrabook and Linux, out of the box, visibly improved the overall performance of the machine, with no need for benchmarking. After tweaking and fine tunning, it only improved.

After that came a long series of Asus, a few HP, one or two Dell. Always flawless installs, out of the box. The only exception I can remember of was a very specific HP model where the modem had to be manually installed.

Having a hand full of companies designing and building for linux feels like being part of an exclusive, Apple-like club; the prices are high, the choice limited.

We should be pressing the industry to recognize the linux ecosystem for what it is: a stable OS, with an ever growing user base with money to spend that want quality support for the equipments they buy.