About a year and a half.
To be honest it’s not “easy” to use. The guiding principle behind mainline packages is that everything has to be built from source, so most somewhat unpopular things are missing from the mainline channels.
To use it like any other distro you’re going to need to learn how to write packages fairly quickly. Luckily the main draw of guix is the entire OS being based on guile so once you get a little under your belt you can just read the specs from other channels to see how a package is written.
Took me maybe a week to start writing guix packages.
There’s also The toybox
Some additional nice things about guix:
Everything is guile. The system definition, the service definitions for shepherd, everything.
Shepherd is hands down the best init program I’ve ever used. It’s just incredibly simplistic but because it just runs the guile definition you give it, you can do some incredibly complex things that systemd etc. can do as well.
The OS documentation is built into the distro, with “info guix” you get reams of configuration information for the distro without ever needing to look it up online.