It's good enough to work, but that's pretty much all you'll get. In many aspects each monitor isn't treated separately by the DE. For example you only have one task bar and each screen gets an exact copy of it. Any minimized window will appear on all the task bars on all your screens no matter what screen that window was from. Right there it's a big turnoff for me. I don't remember the details but just getting a different desktop background for each screen needed a workaround solution as well. They clearly didn't allocate any resources for the multiple display user experience. And now that I've gotten a taste of the insane customizability of KDE Plasma I don't think I'll be able to go back. 6.2 added a layer of polish to the experience that made it perfect for my uses. Which is a shame because Mint was pretty solid otherwise.

I haven't tried xfce and mate on a multi display setup so I don't know. But these seemed to be simpler, being made to be lightweight for less powerful setups so I wouldn't expect them to be as advanced as Plasma for that.

I can't be bothered to learn how to build and maintain a kernel though, hence why I stay away from Arch. My "dummy-friendly" distro of choice for KDE Plasma is OpenSuse Tumbleweed. It has been rock solid for a year now except for that one time a few weeks ago when NVidia dropped the ball and fucked up their driver update. It was fixed a few days later. My only other complaint is that I wish they didn't wait for NVidia to put the new 560 drivers in the production branch to trickle it down to us because for some reason that's what gets supported in tumbleweed. EVERYONE who needs those drivers are impatiently waiting for just that because pre-555 drivers don't play well with Wayland.

Fedora Plasma Spin is probably another solid choice but for some reason on my computer it just instantly bricked itself upon first update.