The shortest answer -

Arch has really good documentation and a release style that works for a lot of people.

Ubuntu is coorporitized and less reliable Debian with features that many people dont need or want.

Arch requires reading the manual to install it, so installing it successfully is an accomplishment.

It's rolling release with a large repo which fits perfectly for regularly used systems which require up-to-date drivers. In that sense it's quite unique as e.g. OpenSUSE Tumbleweed has less packages.

It has basically any desktop available without any preference or customisations by default.

They have a great short name and solid logo.

Arch is community-based and is quite pragmatic when it comes to packaging. E.g. they don't remove proprietary codecs like e.g. Fedora.

Ubuntu is made by a company and Canonical wants to shape their OS and user experience as they think is best. This makes them develop things like snap to work for them (as it's their project) instead of using e.g. flatpak (which is only an alternative for a subset of snaps features). This corporate mindset clashes with the terminally online Linux desktop community.

Also, they seem to focus more on their enterprise server experience, as that is where their income stream comes from.

But like always, people with strong opinions are those voicing them loudly. Most Linux users don't care and use what works best for them. For that crowd Ubuntu is a good default without any major downsides.

Edit: A major advantage of Ubuntu are their extended security updates not found on any other distro (others simply do not patch them). Those are locked behind a subscription for companies and a free account for a few devices for personal use.

I don't know about everyone else, but the last couple of years has had the most unstable Ubuntu releases, with the most unrecoverable releases when issues happen.

I've since moved to Fedora for desktop and straight Debian for server.

I don't really have a concise answer, but allow me to ramble from personal experience for a bit:

I'm a sysadmin that was VERY heavily invested in the Microsoft ecosystem. It was all I worked with professionally and really all I had ever used personally as well. I grew up with Windows 3.1 and just kept on from there, although I did mess with Linux from time to time.

Microsoft continues to enshittify Windows in many well-documented ways. From small things like not letting you customize the Start menu and task bar, to things like microstuttering from all the data it's trying to load over the web, to the ads it keeps trying to shove into various corners. A million little splinters that add up over time. Still, I considered myself a power user, someone able to make registry tweaks and PowerShell scripts to suit my needs.

Arch isn't particularly difficult for anyone who is comfortable with OSes and has excellent documentation. After installation it is extremely minimal, coming with a relatively bare set of applications to keep it functioning. Using the documentation to make small decisions for yourself like which photo viewer or paint app to install feels empowering. Having all those splinters from Windows disappear at once and be replaced with a system that feels both personal and trustworthy does, in a weird way, kind of border on an almost religious experience. You can laugh, but these are the tools that a lot of us live our daily lives on, for both work and play. Removing a bloated corporation from that chain of trust does feel liberating.

As to why particularly Arch? I think it's just that level of control. I admit it's not for everyone, but again, if you're at least somewhat technically inclined, I absolutely believe it can be a great first distro, especially for learning. Ubuntu has made some bad decisions recently, but even before that, I always found myself tinkering with every install until it became some sort of Franken-Debian monster. And I like pacman way better than apt, fight me, nerds.

 :: Searching AUR for notes...

 -> Missing AUR Packages: SideNote

 there is nothing to read

Is it really? I've always understood the cult around it as a joke.

But seriously, RTFM.

Arch has a very in-depth wiki that's the go-to resource for a lot of Linux users, and it offers a community-driven way to have access to literally anything that's ever landed on Linux ever through the AUR. It's also nice to have an OS that you never have to reinstall (assuming all things go well).

Why that turned into such a cult-meme is anyone's guess though.

I just think its good.

The way I see it, you can have an OS that breaks less often and is hard to fix, or an OS that breaks a little more often that is easy to fix. I choose the latter. 99/100 times, when something breaks with an update, it's on the front page of archlinux.org with a fix.

The problems I've faced with other distros or windows is the solution is often "reinstall, lol", which is like a 3 hour session of nails on a chalkboard for me.

Before Arch that role belonged to Gentoo.

To add, before the change the Gentoo wiki was a top resource when it came to Linux questions. Even if you didn't use Gentoo you could find detailed information on how various parts of Linux worked.

One day the Gentoo wiki died. It got temporary mirrors quickly, but it took a long time to get up and working again. This left a huge opening for another wiki, the Arch wiki, to become the new top resource.

I suspect, for a number of reasons, Arch was always going to replace Gentoo as the "True Linux Explorer", but the wiki outage accelerated it.

I use Ubuntu professionally and Arch at home

Anything that's not Windows is my preference.

I love arch because I know what's in it and how to fix it and what to expect, the community is mostly very nice and open to help

AUR is great and using pacman feels lovely

I also care about learning and understanding the system I'm using beyond just using a GUI that does everything for me

Ubuntu is not bad it's probably one of the most used distros by far

Linux motto is: Use what you like and customize it how you like because there is no company forcing you to do things their way