MaximumRD

I like it fine so far for the couple hours I've tinkered. Interestingly there are "paid" options, obviously I am not using that. Paid gives you things like more customization options and themes etc. As is though there is enough to set it to look like typical Linux or more Windows or more Mac like depending what one is use to so that is nice. Placement of start, menus, app display to mimic those other Operating systems. Normal Linux storefront to download more software for free from the Linux repositories. 

I will likely keep it on for some time, cannot say I like as much or better than PopOS! (that would be surprising) but I tend to keep it on for a while and use over time, it's like a third machine after my main PC and desktop so I don't spend much time with it in the grand scheme of things.

Here you can see a quick video with a nice visual tour of what to expect in the latest core edition (what I have installed)

Now this one is slightly older but longer and descriptive, I watch this guy for Linux content. Worth the watch imho. 

Do you feel like any of these these are an improvement on Ubuntu? Or Mac or Windows?

Improvements? For the things I do Linux Mint, Zorin, Ubuntu are all pretty much the same with difference really only being in presentation or style, I just don't dig deep enough. At heart I will always be a Windows guy through and through as it is what I use the most on a daily basis for years, the rest really is just tinkering. My exposure to MacOS is only what came with this 2011 Macbook, I think I upgraded it as far as I could, if I recall it came with  OS X 10.8 Mountain Lion and I managed to "upgrade" it as far as macOS 10.13 High Sierra after much tinkering 😆

I considered shoe horning macOS Mojave onto it which can be done but it sounded very involved and really would have sacrificed some features on a hardware level and also introduced some glitchy results at best so I stuck with High Sierra for some months getting to know it well enough to understand all the "basics" at least for general use, though I cannot say I really "liked" it more than Windows I just always have a need to understand an OS, never would I have thought I'd be editing Kext files but I even did a bit of that lol. So all this is just to say I don't really consider anything "better" I just know what I like and am more familiar with, there was a time years ago I recommended to a basic user that I thought ANDORID was "better" than IOS, I believed it at the time but the person got an Android and hated it, was totally lost and all of their friends / family were of course on APPLE devices so my recommendation was not a service to them, I cannot think like that, only what would be best for the person and not from my point of view.

Today of course after much exposure I'd take an iPAD over an ANDROID without thought 😜though I really still want a good ANDORID tablet. So to me it's up to the individual to just try and see what they like best, listen to people smarter than I comparing Linux / Windows etc, someone who uses each as a daily driver in some form because I am bias in that I will always go back to what I am more familiar and comfy with every time which for me is WINDOWS, all the other platforms for me are just tinkering. Sorry, I cannot answer better or just give you a simple straight forward answer to your  simple question. That's just me and the way my brain works. I turned to Linux Distros on the Macbook because I could not take MacOS any further on it and so my thinking was the best way to get a modern and supported OS on it was to switch to LINUX, first I tried was Linux Mint If I recall and really in that respect I could have left it at that but my mind is easily swayed by fancy new distros and features, I probably tried like 5 different Linux distros, some worked, some were dead in the water. seeing that System76 own Linux machines came with their PopOS I of course had to give that a go and honestly, was very happy for the last several months, it just worked straight away, all features and function keys etc. But I just get bored and never settle so decided to take a chance and try ZorinOS.

No doubt another Distro will catch my eye in 3 months or 6 or a year from now. I WILL SAY THOUGH outside of basic use and functions which many might be happy with ANY Linux distro, even ones designed to ease the transition from Mac / Windows, there is always a learning curve or a moment when you have to get your hands dirty in Terminal or other areas that are not as intuitive as Windows or Mac. I've managed to muddle my way through thanks to people smarter than I who post the directions online, at least I AM good at Googling and following directions. 🤷‍♂️