As far as I'm aware - and I may be mistaken - Xfce is more popular than MATE as a desktop. After all, it's advertised as lighter, faster, more customizable, and more modular.
However, is this really true? Is Xfce really this magical DE that is as capable as it is advertised? I'd argue no. This article is meant to explore why, and in particular its relation to a similar overall DE in MATE.
For what it's worth, YMMV. While I for one cannot see the lightness of Xfce at all, many people have found it. Machine variance is a thing, and while I have tested across a multitude of devices, I can't 100% guarantee your experience will be the same.
I'm also aware that this is a topic that will inherently cause a lot of vitriol. To be clear, I'm not suggesting Xfce is bad. Feel free to write against this article with an actual counterargument. You're also free to suggest both suck because they're not tiling WMemes but if so I personally request you to shut up about the fact you use a tiling WM already and actually go do work with it. It does make you more efficient after all right? Put it to use!
I'm assuming you're already familiar with both of these DEs. If not, well, Xfce is an independent desktop environment that aims to be fast & lightweight while still easy to use and visually appealing. It also aims to be relatively modular - one in theory should be able to install various parts without excessive dependencies that make this impossible. Contradictory to this end, it also offers development libraries to help integrate things - for instance, Thunar requires a ton of these libraries, so this doesn't hold up. MATE is the continuation of GNOME 2, which had a more traditional layout and general philosophy compared to GNOME 3, which holds a more touch-oriented layout and a new design philosophy to go with it. MATE's goals are the same as GNOME 2's, with the added goal of keeping MATE up with the times (for instance, GNOME 2 used GTK 2 while MATE uses GTK 3). You can read about Xfce and MATE here. I'm mostly reiterating points from my reviews here.
With that all being said, and as said in my review, Xfce does not live up to its expectations. Let's take a look at what it claims vs reality, as well as a few other points:
Let's compare this to MATE. MATE used less resources for me, has clearer menus, has great default apps (Pluma text editor/Caja FM are amongst the best in their respective fields), and sane defaults (outside of the layout) while being prettier out of the box. Seeing that it's super easy to get a similar layout as Windows or Xfce, what reasons are there to not pick MATE over Xfce?
Let's be up front here - there are none. MATE objectively outclasses Xfce in various fields and in my opinion outclasses it in basically all of the rest. It is hands down the better DE, especially for 1. beginners 2. older machines. There is genuinely little incentive to use Xfce over MATE, unless your machie and your tests show that MATE is heavier than Xfce, and even then I'd argue MATE might still be worth considering. It's clear - MATE is the better DE.
(wip: Why care? Because pretending Xfce is something its not is going to confuse and divide newcomers that deserve a better experience.)
But hey, maybe I'm wrong. Maybe MATE isn't really all I'm suggesting that it is, and maybe Xfce works perfectly fine for you. Even if MATE does work better for you, why move from something that you've already established? It's not like Xfce is this terrible demonic DE after all (and I don't think it is!) so why not just make it work?
The main reason to do this, imo, is for newcomers. Imagine John, who is told Xfce will save his 2006 Dell Vostro 1520. He boots it up, finds it horrendously ugly by default, and notices that his keyboard shortcuts are off by a bit. After spending a ton of time ricing it up he finds that it's now too heavy to run well. John at this point is jaded and either he ends up quitting Linux and throwing the old box out, or he runs into MATE and finds that it was what everyone said Xfce was.
I'm in a similar position to John. I originally thought Xfce was it. I loved how simple it was and how it looked and swore upon it. I was afraid to use MATE because I thought it was basically a heavier Xfce. But over time, upon realizing Xfce wasn't lightweight on my machine anymore, and upon testing MATE out, I've turned aroudn and now Manjaro MATE is my daily driver (and what I'm writing this on!).
Either way, why not run the best you can? If you've never tried MATE, it is absolutely worth giving a run. You'll find that it really is an improved Xfce in all ways.
And it's not like Xfce doesn't have the power to get its act together. I've heard from my various chats that Xfce just changed to client-side decorations - the aesthetic GNOME pushes hard - off of the back of one dev who went out of his way to do this work. Why do that? Why not focus on actually fixing the memory leak bug that happens wehn you theme it? Why not implement actual zoom-in for Mousepad, which has been open for quite the while now? Even though Xfce has a much smaller dev force than MATE, there clearly still is the potential to fix the outstanding issues Xfce has. By choosing to not use Xfce and to use MATE instead, we force Xfce's developers to actually respond to our concerns or lose users. Instead of wasting time on features that we actively dislike, they will learn to fix up what we need to be fixed.
We have to criticize Xfce for those who don't know better. We can't let its reputation speak for itself anymore, because it no longer warrants that reputation. Otherwise we're willingly letting newcomers be misled. We have to do better than that.
So hopefully I've proven that MATE is better than Xfce. I really don't see a way personally how its not - in terms of everything that a DE directly affects, MATE does it better. It's easier to customize, it's lighter and faster, it has better defaults and apps, and its arguably more aesthetically pleasing as well. MATE is just what Xfce advertises itself to be.
The main reason to make the switch is to show that MATE is the better DE for newcomers. To mislead the newcomers by pretending Xfce is better is a grave mistake, as is to shill Xfce as something its not. By choosing MATE over Xfce, we avoid this mistake, and we tell Xfce to get it together or be forgotten to time.
And finally, while I've taken a harsh approach towards Xfce, I am in no way implying it's a terrible DE. It's honestly quite nice and has quite a lot of nostalgia for me as the first DE I had a good experience with it. But we must criticize the things we love for them to improve. If Xfce was genuinely what its cracked up to be, I would likely still be using it today on some machines. For that to work, however, Xfce needs to re-evaluate its priorities and get things straight.