Debian is rock solid, there are even more user-friendly distros though. In a few edge-cases it will expect you to know your way around things, however there are a lot of guides for it. Going with this will cause the growth of a mighty white beard!

Arch Linux will make you cry. If you want to learn how to fix and configure things it’s great (and their wiki arguably is the greatest of all), but their lack of QA and expectation to do that yourself often causes issues. You’ll probably cut your fingers on its bleeding edge. If you want to learn with less bleeding I’d recommend CachyOS these days. I’m certainly not saying this because my computer didn’t boot after updates multiple times. /s

HOWEVER if you have an Nvidia GPU, first off: I’m so sorry. Secondly, you absolutely (!) should use a distro that takes care of their driver for you. Their drivers are hot steaming garbage that you do not want to meddle with (many distros try their best to do it for you, but often enough it won’t work for some people). See below, Nvidia distros marked with recycling symbol.

A few other options to consider with noticeable features:

• Bazzite (♻️): If you mainly play games. User-friendly, most compatible with handhelds next to CachyOS. Takes care of a lot of small things related to gaming.
• Fedora: If you want modern features on a very stable system. Very good ecosystem. Basically the other stable workhorse next to Debian. Will spawn a nice hat on your head, m’lady.
• OpenSuse: Also very stable, best distro for those concerned about US influence (it’s strongly EU-based). Tumbleweed arguably most stable rolling-release distro (newest system software) with a great graphical settings’ tool YaST (future unknown, unfortunately). Leap is rock-solid but slow, meant more for Office PCs and Enterprise users. After installing this you’ll suddenly start talking german.
• Linux Mint: If you want things to just work with the flattest learning curve possible for former Windows victims. Helpful tips for Ubuntu usually apply and that weird software offering you a manual download for Ubuntu will just work.
• ElementaryOS: Very good for users used to MacOS, probably flattest learning curve for them. Great accessibility! Not as feature rich as others (their whole desktop is made in-house, so it’s very cohesive but a lot of work for them), but what they have is very well tested.
• ZorinOS (Core): Also very good. Most likely the one with the biggest software selection from the start (comes with both Snap and Flatpak pre-configured). Probably the one you’d eventually find on some school computer.

And three others interesting if you might buy new hardware soon (damn, you rich):

• TuxedoOS (♻️): Default OS on devices from Tuxedo Computers (EU). Works on any machine and is a really nice distro in general.
• SlimbookOS (♻️): Default OS for Slimbook (EU) devices. Also nice.
• Pop_OS! (♻️): Default OS for System76 (US) devices. They’re currently developing a whole new desktop environment (Cosmic), so their normal release hangs a little bit behind. It’s okay though. Be aware it’s from a US company (not just maintainers, but commercial entity). Fucked up Linus Tech Tips once.

Depends a bit on what you want to do.

Debian stable tends to have rather old versions of everything, but Debian testing (currently codename Forky) is really nice. I installed it a few months ago on my ThinkPad, and it’s running beautifully.

I’m not in it for the uptime, so I shut down whenever I’m done and when I shut down, I do an update / upgrade, and there’s always something being upgraded. I’ve had zero issues with stability or performance.

I have no experience with Arch, so I can’t really compare.

Arch is a challenge, be prepared to spend more time learning and tinkering than using your computer for the first few months (and forever). It’s not impossible, but you will most likely have to reinstall a few times as you learn. If thats what you enjoy, great. Go for a distro made for the lay person like Mint or Bazzite. There’s a backup program called Timeshift, it will replace windows snapshots and can help you recover from mistakes without having to start over.

If you put your home drive on a separate partition/drive it will be easier to distro hop as you try different ones. Still, make sure your data is backed up, ideally put the backup on an external drive that you can unplug while installing new a OS.

Why have you forsaken God? You should be praying in TempleOS.

If you know vaguely what you’re doing or are willing to learn, you can go with whatever and it’ll be fine.

Personally not a big fan of debian because they tend to be slower and more conservative on updates. Arch is a bit more technical, but very customizable.

I’m personally a big fan of Fedora. Software updated quickly enough to have all the bells and whistles, slow enough to not get cut by bleeding edge software.

The fact that you’re asking this suggests you might be new to linux so go Mint but if it has to be one of those two then Debian

NixOS ;)

If you don’t care, go with Mint. Fast, secure, simple.

If you have some special thing like an old slow computer, uptime or specific security needs and so on, check out all the other good answers here in the post.

free as in free beer: literally any distro other than winux/linuxfx/wubuntu free as in libre: trisquel

What do you mean by free? Why did only those two make your list?

In general, I recommend Fedora KDE Spin (or Fedora Kinoite if you know what containers are)

For your question, I would go for debian. But the answer also depends on your use-case. Software dev? CLI user? Gamer?

If you are interested in maintaining your OS as an ongoing and constant project, go with Arch. You will learn a lot about Linux, and about system administration in general. You will also have entire days where you are unable to do anything productive with your computer because the last update broke userspace again and you can either spend a lot of time troubleshooting your specific problem, or spend a lot of time reinstalling and reconfiguring your system.

If your computer is more than just a hobby platform and you need to use it regularly for any kind of productivity, go with Debian. Set it and forget it.

Either way, off-system file backups are recommended.

Is your hardware ten years old or more?

Do you want a system made up of software that is on average 3 years old?

Do you want absolutely ridiculous stability for the uptime memes?

Are you a fan of the idea that every design decision should be done by a committee of theoretically democratically chosen developers but is actually just whoever wants the job because there is never any real transparency or motion about when the meetings are, much less when elections are?

Does the idea of your operating system being compatible not because its good but because it’s just the largest base thanks to corporate investment make you moist?

Then pick Debian.

If you answered no to literally any of those options then go ahead and pick an Arch flavor, or Arch itself.

I mean, you can install each in a VM if you want to play with them.