I'm reading through the #guix manual, and just realized something (I think):
The way Guix sets up `substitutes` means that I could compile everything from source on my powerful desktop* and then set that as a substitute for my laptop—which would then pull down the binary packages from there.
(*NOTE: I don't have a powerful desktop, but I have hopes/plans to get one)
This seems like it's pretty close to the advantages of #gentoo without (as much of) the pain!
@codesections this is very much how I use Nix/NixOS, often also taking advantage of cachix.org -- not sure if guix and cachix work easily, even with guix using nix at lower level. Might work trivially, dunno :). Anyway yep substitution is great and is made possible by having builds reproducible and isolated enough that they are safely (among trusted peers) substitutable with confidence everything will work regardless.