It’s mostly an aesthetic choice, a choice between desktop environments.

Desktop environment (DE) is just the visual bells and whistles that you use to navigate the PC, like that quick animation when you minimize or maximize a program (Apple loves this), a start menu that has cute icons for each program and turns blue when you pass the mouse over it (or a start menu that is just a raw list of program names), etc.

Mint Cinnamon uses a DE that looks like Windows 7 reborn, Mint XFCE uses a DE that looks like Windows XP reborn, and Mint MATE uses a DE that looks like Windows Vista reborn.

People will tell you that these DEs will have a slight difference in consumption of RAM, where the most ‘shiny’ DEs will consume more RAM (XFCE<MATE<Cinnamon) by virtue of having more bells and whistles and some different programs that execute the same function, but the difference is irrelevant in practice (unless you are using a 2gb or less PC, where each 50mb of RAM counts). So it’s mostly what you fancy to look at. I just like the old-school visual of XFCE.

You are still a beginner, and in that case almost everyone rightfully says to go to regular Mint only, instead of LMDE or any other distro. A beginner will not know how to evaluate the situation in case of troubles or follow any complex instruction (like anything involving the terminal that is not completely copy-paste). Mint is fully click-click-install now, something that no other distro has equaled. Linux Mint, regular edition, is widely compatible with all sorts of hardware, that in other distros give black screens or esoteric deep s**t at install or later, which is a show stopper for beginners just making the transition.

I myself am not a beginner anymore, and every other distro (save Mint) has failed me at some point. Debian, LMDE and Sparky Linux have not even booted in one notebook, Bazzite (Fedora) has after a few weeks given me a black screen in a desktop pc with Nvidia that i could not solve, and Arch - Endeavour OS - Manjaro have simply collapsed after a few months (probably by using AUR, which is supposed to be their main advantage, but i could not even discover the source of the problem, in each). Everything was restored in order after a blanck install of Linux Mint XFCE, which is the only distro i use now.

His-Her complaint seems to be somewhat popular, lots of obligatory hand-holding is present when options that turned it off would be as simple as a few lines of code, and they ruin the slow stages that require thinking or the fast action ones.