It’s far better in theory, but in practice it’s got some massive issues:

• non-free packages are taboo in the official guix community
• binary support was lacking the last time I used it (firefox didn’t have a precompiled bin for example, and that means you need to leave your browser to compile overnight)
• far less packages than nixpkgs even when you account for the non-free repo
• packages are seriously out of date (I tried using it as an additional pm a few months ago, and debian 12 was newer in a lot of cases)
• essentially no support for some programming languages and package managers (node and npm for example)

In it’s current state it’s really only good for emacs, lisps, and some other languages like haskell.