I've had at least one computer with regular Mint + Cinnamon installed since V19 and it's always worked well for me. I somehow only learned about LMDE last month and since I've previously run Debian I figured I'd give it a shot.
I took the drive with my LM22 installation out and installed a brand new 1TB NVME, put LMDE "Faye" on it and YIKES.
I'd forgotten how "raw" regular Debian is in nearly everything from Grub to package management and even Cinnamon is somehow less sharp and sort of lackluster on LMDE.
The first boot up went okay but trying to swap the nouveau drivers for the Nvidia drivers did not go well at all and somehow ended up with all the fonts and icons broken.
I couldn't figure out how to fix it and decided to simply re-install LMDE from scratch, no big deal.
On the 2nd install I started getting AER errors on boot and every time I rebooted I got more of them. At one point the DE locked up entirely and I had to manually power cycle the machine. I couldn't get to the desktop after because of an endless string of AER errors.
In between reboots, while I could still get into the desktop, I was installing updates and while that process was pretty much the same as regular Mint it was also slower, even after changing over to the fastest repositories available. The update manager also didn't work as well. For instance the first update run said it was complete and wanted a reboot but before I could do that the update manager automatically ran again and it showed me all the updates it had just installed as needing installed again. WTF?
After frustrations with the Nvidia drivers, the weirdness of updating, broken desktop environment, and the AER errors I decided to see what would happen if I installed regular LM22.
With LM22 on that exact same hardware, including the new NVME, everything works perfectly. No errors, Nvidia drivers installed without issue, updates worked as expected and Cinnamon looks and behaves just like you'd expect.
Swapped out the NVME for the original drive that had LM22 on it and it too works just like I'd expect.
I'm not running weird-o hardware either; it's a Gigabyte motherboard and an Intel i5 10700k with 32G of RAM and an Nvidia 2060. No overclocking or performance tweaks.
I have no idea what I did wrong, if anything, or why LMDE seems to hate my hardware but for me on that system LMDE is not at parity with regular Linux Mint.
LMDE is the future. Not the the present, yet.