For me it's PeppermintOS.
I started my Linux adventure a few years ago, and haven't owned a Windows PC since.
I currently use Arch on my main rig, and I wanted to install Linux on two old laptops that I found laying around in my house
I then remembered the first distro I ever used, which is PeppermintOS, and I was amazed at the latest updates they released.
They even have a mini ISO now to do a net-install with no bloat, with a Debian or Devuan base.
Sadly, I believe the founder passed away a few years ago, which is why I was really happy to see the continuation of this amazing project.
How is Guix for disk user use? As soon as I install nix (the tool, not the OS), it immediately eats up 2Gb of hd space… before installing anything. I wipe the install and then forget for a few months, rinse repeat.
Guix looks a lot cleaner to me, but I haven't tried it yet.
In fairness, when you install the nix package manager you’re going to get a full toolchain with all necessary dependencies in addition to your system ones. On NixOS these are your system ones as well so you don’t necessarily have duplicates. The same will be true of Guix afaik.
Maybe use btrfs, which has reduplication and compression capabilities. I never tried it in Guix but it's like magic.