Excerpts from Marc Heiler's message of Sat Jul 16 04:10:44 +0200 2011:
> Yup, nixos is a GREAT idea. Always was much more sophisticated than 
> Gobolinux (I am still sad that Gobolinux is more or less dead :( )
It depends on what you want. nixpkgs was designed to generate results
you can regenerate on a different machine (if possible).
That's a unique feature. It was also designed to offer atomic upgrades.
From this point it follows that it should support multiple versions.
Because you may still be using 

> How I understood it though, NixOS does not retain the elegance and
> simplicity of Gobolinux?
Well. Don't use a computer but a pencile. You can't be more simple :)
I mean if you want the features described above you can't make it
simpler.

> Interesting, especially the atomic upgrades while retaining 100% of
> the old behaviour set.
Well - its not quite true. Application state (eg gimp's configuration)
is stored in ~/.gimp. Unfortunately it also has some pointers to
/nix/store/xxxxx-this-gimp-build. Thus if the hash xxx changes your
~/.gimp is broken. This results in gimp no longer being able to open
jpeg files. However this kind of problem is rare and it can easily be
fixed.

> I think in my current workflow, I'd prefer to use nixos on top of
> an existing linux installation though. I have become very lazy
> and reluctant to install something new, even if it may be better,
> it kind of breaks my workflow, and I don't like that.
nix: the package manager
nixos: the linux distribution based on nix (and the nixpkgs build
       descriptions).

The nice thing: because everything is in /nix/store it does not
interfere with your existing system much.

Do whatever you want :) I wanted to make sure you don't miss nixpkgs
cause I think it the best system available. There are some drawbacks
though. Eg if you rebuild bash everything has to be rebuild because you
want deterministic results :/

yours
Marc Weber