I came from Linux Mint, and at the time was using the KDE Desktop. I had to make a decision because if I was going to stick with KDE, I wanted a distribution that supported it natively. Ironically, I’m using the XFCE desktop now, which meets my needs and more. I still read Clem’s monthly blog. And the forum was always respectful and helpful.
I wanted an estalished distribution, and was looking at moving away from a fixed release distribution. I had already discounted slackware, redhat or related, and opensuse. I had been running arch on a VM for some time.
It’s helpful if you can describe what you want in a distribution. There are technical, usage, and philosophical differences. It’s good to stretch and learn, but the grass isn’t always greener.
A couple of main differences, from an end user’s perspective. One is the type of distribution. Manjaro is a rolling release and Ubuntu (based on Debian) and Linux Minut (based on Ubuntu) or LMDE (based on Debian) are fixed releases. Another difference is how software is packaged, therefore the tools you use to install, remove, and update software. The utilties that come from gnu.org or freedesktop.org, or the applications like gimp, libreoffice, blender should be the same. But each distribution, will have their own default settings and homegrown applications. Each distribution supports a different set of desktops, and may customize them.
Here is my original response, why I’m using Manjaro, when it was fresh in my mind.
This site distrowatch might be helpful.
Also this youtube channel, OldTechBloke. He has specific videos on Manjaro, Arch, Linux Mint and other distributions… imho, he does an awesome job. Really, he’ll discuss the topics you need to know to increase your happiness as a linux user.
PS: I once got flagged by a user on this forum for simply suggesting pamac as an alternative to yay. Oh well. I value hearing people’s experiences. You never know what you might learn, or be able to give back, in a good way.