I've seen some murmuring that the more "ultrabook" they become, the less dependable. In which case, I would probably just stick with the Dell XPS line, which I've been pretty happy with so far.
I've enjoyed them for many years too. My first Lenovo "ultrabook" was X1 Carbon. It was quite obvious that there were very few (perhaps none) CRUs on it. But it has served me for 4 years and still works. The battery discharges faster now of course.
So late 2019 I got an X1 Yoga to replace it, 2nd Lenovo Ultrabook. So far so good.
I work in Fedora every single day, very extensively. I find these laptops and Fedora to be very dependable. But of course that means little because people who run OpenBSD make the same claims.
I am currently very happy with a T495 and Fedora. I ordered it soon after it launched in the US, gambling that the chipset issues were mostly resolved with other machines that launched earlier with the same AMD Ryzen platform. I first installed it with Fedora 30 and upgraded to 31. There was one weird kernel update that would not boot without custom boot params. I think that was addressed with both later kernel updates and also a BIOS update that made some ACPI changes.
Mostly, I've seen Thinkpads that still worked fine when they were long in the tooth and I upgraded as work budgets cycled. This history includes (as best as I can recall): X20, X22, X40, T40, T41, T61, X200, T410s, T440p, T460s, and now T495. I had brief encounters with Dell, Hitachi, and Sony before that first X20.
Over all the years, I've had a few types of hardware failure. The worst was a T41 which failed thermally and had its mainboard replaced at an IBM service center. I also had a heatsink and fan replaced on the X200 because it made an annoying vibration at times. I had an Intel SSD fail abruptly in a T440p. I also had a key jam and then eject itself on that T440p, requiring a new keyboard. I had fluorescent backlights go pink and fail in the old days. An of course I've had batteries lose their capacity over time.
I've upgraded the SSD on a few devices to add space after a couple years, and I bought an aftermarket battery once. But, generally I've provisioned the machine with the RAM and wifi I wanted on day 1 and never touched it again.
The other is a T450s from about 2014. It is very light, but not an X1 Carbon so it is still pretty "thicc" and modular.
Neither machine will probably compare to the IBM days. They're tricky to disassemble and their components are not as modular as back then. But they are a lot more IBM-like than, say, the MacBook Pros of their respective eras -- even though the 2014 one comes from the era when Lenovo switched to chiclet keyboards.
It's a bit of a nuisance to have to change audio inputs and outputs with the Pulseaudio pacmd but maybe there's a better way I have not yet discovered.
Also as a long time Macbook user I am not happy with the Lenovo touchpad. This has been the topic of a call to action and many discussions such as https://news.ycombinator.com/item?id=19485178
From the product line I think officially they only support the XPS13 on Linux. For larger screen sizes you're probably better off with something from the Dell Precision product line.
I have an XPS13 Developer Edition and have also been pretty happy with it. I like that the experience is improving over time as Wayland and Firefox get better. IMHO the XPS13 is somewhat like a 11" MacBook Air but with 13" screen and a quad-core processor.
That said, I wouldn't not recommend the Dell. It's my second Sputnik system from Dell and this one had way better support out of the box.
Disclaimer: I am not a grey-beard.
So I ended up buying a used T480 on eBay and then completely gutting/refurbishing it. I'm talking display swap to get the 1440p panel, keyboard swap to get the backlit keyboard, trackpad swap because the one it came with was grungy, new SSD, maxed out RAM, clean out the inside, new thermal paste, new internal battery, new external battery, etc. I didn't replace the motherboard, RTC battery, fan/heat spreader assembly, webcam(s), hinges, or the external shell, because they were in pretty good shape, but it wouldn't have been difficult to do so.
I've upgraded laptops before, but it always seemed a little more perilous than upgrading a desktop, because I was always afraid of braking something, or not getting it back together properly. I'm really glad I took this route, because I no longer feel like I'm walking on eggshells. I can take this thing apart and put it back together blindfolded now, and if I accidentally break something like a snap, I know I can either work around it or get a replacement.
Construction on the T480 is still very good. Lots of magnesium on the core structure, captive screws, connectors everywhere, clever layout to make (dis)assembly easy. Unique parts are easier to get than I expected. You can pay full price and get them from Lenovo, but you can also usually find them new for a little (sometimes a lot) less on eBay.
The T480 is probably the best Linux laptop I've had so far (Previously I've had a T520 and a T60). Somewhat ironically, the only complaint I have about the hardware has to do with that battery hot swap feature that I wanted. The charge controller decides which battery to discharge when they're both charged. It prefers to draw power from the newer / less worn out cell first, and on my machine that seems to be the internal cell, and probably only because it came with a few hundred mAh more capacity than nominal, while the external battery was right around nominal. What this means is that it draws the internal battery down to 5%, then it discharges the external battery, and by the time you'd want to hot swap the external, the internal is somewhere between 0 and 5%, making the hot swap seem precarious at best. You can individually tweak the full charge thresholds to keep the batteries from wearing out prematurely, but you can't change that 5% threshold, and you can't change the discharge order. Maybe someone will write better firmware for this thing at some point. But still, I get like 15 hours of battery, and coach on long haul flights usually has an outlet now, so it's not a big issue in practice.