All my current boards have 3d printed cases so I don’t have much to compare it to. I’ve also been thinking about different plate materials and seeing how they change the sound profile, but haven’t actually started building anything yet. Chewiedies on Printables has designed gasket-mount 3d printable cases for a number of boards, which I want to try out before I start designing anything new.
Not a fan, mainly because it’s proprietary. Canonical hosts the only repository and you can’t change it. The file system stuff is secondary.
I do think Flatpak is alright, and I use a few Flatpak apps, but since I use Arch, I generally prefer to install things from the AUR.