Why switch?
I played with the idea of switching for quite a while. Having switched my daily driver from Windows maybe 6-9 Months ago I made many mistakes in the meantime.
Good and bad
This may have led to a diminshed experience with ubuntu but all in all, I was very pleased to see that Linux works as a daily driver. Still, I was unhappy with the kind of dumbed down gnome experience.
Problems
There were errors neither I nor people I asked could fix and the snap situation on ubuntu (just the fact that they’re proprietary, nothing else).
Installation
Installing debian (and kde) was easier and harder than I expected. The download mirror I used must not have been great although its very close to my location because it took ages although my internet connections is good.
Apps
Since I switched to Linux, I toned down my app diet a lot. Installing all my apps from ubuntu was as easy as writing a short list and going through discover. Later I added flatpak which gave me a couple apps not available through discover (such as fluffychat). The last two I copied directly as appimages.
Games
I was scared that the „old kernel“ of stable debian would be a problem. As it turns out, everthing works great so far, a lot better than on ubuntu which might or might not be my fault.
Instability
Kde does have some quirks that irritate me a bit like installing timeshift (because I tried network backups which dont work with it and the native backup solution does not seem to accept my sambashare) led to a window I could only close by rebooting.
Boot time
What does feel a bit odd is the boot process. After my bios splash, it shows „welcome to grub“ and then switches to the debian start menu for 3 seconds or so, then shows some terminal stuff and then starts kde splash and then login. This feels a lot longer than ubuntu did. Its probably easy to change in some config but its also something that should be obvious.
Summary
So far I‘m incredibly happy although I ran into initramfs already probably because of timeshift which I threw out again. I might do a manual backup if nothing else works. My games dont freeze or stutter which is nice. All apps I had on ubuntu now work on debian and no snaps at all.
TL;DR: If you feel adventurous, debian and kde are a pretty awesome mix and rid you of the proprietary ubuntu snap store. It also doesnt tell you that you can get security upgrades if you subscribe to ubuntu pro. Works the same if not better.
To clarify, Cosmic desktop is not the default. It’s very much a WIP. Pop OS uses Gnome by default. They add some nice customizations to it too like tiling support and some enhanced power management options.
Pop OS is Ubuntu based, but they replace Snap with Flatpak, package a kernel as close to mainline as possible, and include Nvidia drivers (if you grab the Nvidia installer ISO).
I used Pop for a few years, loved it. Last I used it they still defaulted to Xorg instead of Wayland and that was a no go for me with an eGPU so I switched to Opensuse.