funnily enough I tried the same sort of switcheroo a few weeks ago as well and just ran into too many issues for it to be useful for me at the moment as well. I tried to contribute back fixes for the the problems I ran into, but just couldn't figure out how to fix all the problems I had with the way things were being done :( PostGIS and a few Gnome 3 desktop issues basically drove me back to Arch where stuff just works.

I'm sure I'll try nix again, and again, until maybe one day it just works as well. I really do love the features it brings not just on paper but in practice.