> I'm a fairly happy arch user, but if I could drop a Guix userland
> distro on top of it, I could easily see myself doing that full time.

Guix can be used as a package manager.  Try something like the following
(I suggest to create a chroot first):

$ git clone git://github.com/NixOS/nixpkgs.git nixpkgs-github

$ git clone git://git.sv.gnu.org/guix.git
$ cd guix
$ ./bootstrap
$ ./configure --localstatedir=/nix/var --with-nixpkgs=nixpkgs-github
$ make && make check

(You might need other packages [1].)

If you don't want to run 'make install', you'll have to prepend
'./pre-inst-env' (it sets the needed variables) to all commands.  For
instance, this command should build GNU Hello:

$ ./pre-inst-env guix build -K hello

Don't forget to run the daemon [2] prior to that:

$ ./pre-inst-env guix-daemon --build-users-group=nixbld &

Also, it seems that your current distro contains non-free packages.  I
highly recommend you to switch to a free one [3] (e.g., Parabola [4]).
There is a guide that might help [5], but I haven't tried it myself.

> Linux distro

Please don't use this term [6].

Don't hesitate to ask if you have any questions.

[1] http://git.savannah.gnu.org/cgit/guix.git/tree/README
[2] https://gnu.org/software/guix/manual/guix.html#Invoking-guix_002ddaemon
[3] https://www.gnu.org/distros/free-distros.html
[4] https://parabolagnulinux.org
[5] https://wiki.parabolagnulinux.org/Migration
[6] https://www.gnu.org/gnu/why-gnu-linux.html