I only moved to it because it's free (as in beer, not as in speech, but it is also free as in speech), but it turns out a lot of distros are just better than Windows and Mac OS now. When I switched from Windows 7 to Windows 10 it wasn't quite there yet, but it's fully transformed from the OS for nerds to the OS for anyone:

• Quicker and easier to install even without the "try before you buy" mode Ubuntu-based distros provide
• Loads faster
• Basically the same UI - you won't need the command line unless you're trying to make advanced changes
• Customisation of every element is nearly unlimited - you could easily change the start button to shrek's face, for example
• Programs of all types are easier to find, install, and uninstall
• Programs generally load faster and run more smoothly
• Windows games generally run more smoothly and occasionally even at slightly higher framerates
• No ads or bloatware or background data collection getting in your way and sucking up your resources
• Can't run modern Call of Duty games (unfortunately many older ones do work)

Anyone who can follow half a page of simple step by step instructions is qualified to install it (the most complex part is flashing an .iso to a usb (a program does it for you)), and everyone who has used a computer is qualified to use it. At its simplest, with distros like Mint and Pop!, for the casual user it's the same experience as the mainstream OS's - or rather the experience they expect before the system throws the inbuilt bloat at them. When you get more specialised, especially on gaming distributions like SteamOS or Bazzite, it's a much better experience even for advanced users, as various utilities are preinstalled and preconfigured, minimising your time setting up. You can go up or downstream to find a distro with as much or as little as you need and then add as much or as little as you want to get your ideal computing experience.
There's also Arch, which we will only be acknowledging.

I thought that switching to Linux would be as big a jump as when I moved from Mac to Windows, but moving to Mint, trying Ubuntu and Kubuntu, then settling on Bazzite has just been a series of small, shuffling steps. Recreating a similar setup to what I had in Windows has been as trivial as it was time consuming to do originally, while still providing the option for much finer tuning - On Bazzite I had to install a grand total of 4 programs to recreate my software setup because the included utilities covered so many things I'd had to find programs to do in Windows.

As far as I can tell there's only one real downside, and it's one that only really matters to advanced users: if you tell Linux to do something stupid or that would break the OS, where Windows will do its best to stop you and Mac will ask where you learnt those words, Linux will simply ask for the password and then gleefully snap it's own neck. It doesn't matter if you meant to or not, you will have to reinstall and reconfigure it.
But like I said at the start, that's real easy, so it's not much of a downside.
The less real downside is that some specific games and applications won't work even with the translation layers, but you can always dual boot for that one thing.

You can switch because you hate corporations, or closed source software, or spending money, or for opsec, or because you're a big fucking nerd (Arch btw), or any of the traditional reasons for using Linux, but the main reason to switch over is because it's simply the superior product. The power of Windows and the simplicity of Mac OS, without sacrificing any of Linux's extensive customisation. I don't know how long ago it truly overtook the competition, but it definitely has done.
Just download Mint and give it a try - if you need something more specific you'll know and can explore further, but for most people it has everything you'll want ready to go.
Also if you don't switch you're a fucking liberal.