I have never used nix or nixos. I liked their shared idea (functional, atomic, reproducible systems), and so when I looked at their differences they seemed to all be pros for guix:
- Clearer, more robust, more centralized documentation
- GNU Project
- Guile Scheme (Lisp) as opposed to Nix DSL
- Unparalleled emacs integration
The only bittersweet aspect of guix compared to nix was the foss only stuff, as I do need some proprietary drivers, but nonguix is so easy it hasn't been a practical issue. And of course I am big advocate of free software so I like that guix is pushing that forward.
There's also a theoretical issue that guix has less packages, but the standard channel + nonguix has had everyhing I use.
Lemmy has certainly already won me over reddit. Going back to centralized social media is something I will actively avoid if at all possible.
However I believe nostr is a theoretically better protocol than activitypub. Having your account/identity tied so strongly to a particular instance is undesirable. As soon as there is a reddit-like (or even forum-like) client for nostr which is relatively active/polished, I will switch. Nip 172 can't come soon enough.
In addition to being less popular / newer than activitypub, nostr is also full of bitcoin[^1] bros and twitter refugees (not my crowd). But frankly I think complaints about that are like the complaints that lemmy is a place for tankies a couple years ago when people's only exposure was to a (much smaller than today) lemmy.ml.
[^1]: monero support would be nice though...