Okay when I first started using NixOS as a desktop, I knew it would bite me. But I'm a firm believer of the way NixOS handles state, so I suffered through both my and NixOS' growing pains. Basically I had to change my graphics card for some strange reason (which worked on Arch Linux!), ALSA gave me problems with flash videos, this is when I found out how amazing the NixOS community is. They helped me solve this issue quickly, it was a one liner in my configuration.nix. I've had issues with harddrives not being seen on time and having to tell the boot process to wait a second (again a one liner). It's actually quite a fun ride, don't install it on a machine you intend to do real work on, once happy and you've tweaked the hell out of your configuration.nix then roll it out where you need it. So if you have any issues, determine if you can resolve it intelligently and then create a github issue, they are very supportive (thank you Domen Kožar for the quick qt4 fix!). Now my system is happily ticking along, with one nagging Tk issue.