This is more of a personal dilemma, since I keep finding myself switching back and forth between NixOS and Gentoo every now and then. I've done this twice for each so far ever since I immediately started off my Linux journey with Gentoo, making a quick stop at Arch once when I didn't have enough time to set either of them up properly. Both of them provides a massive amount of control over my system and lets me build my system in weird and interesting ways, e.g. musl, clang, and/or SELinux for Gentoo and impermanence for NixOS (it still kind of blows my mind right now). Personally, I find Gentoo more intuitive, but NixOS is more powerful for managing complex systems, but then again, I don't have any complex systems to manage, only a singular desktop system. I'd love to keep switching back and forth, but I feel like it has become sort of a time sink for me, somewhat hindering my studies, and thus I feel the need to decide which one to settle on, and which one to keep in a VM to mess around with. That brings me to the title of the post, which do you think is better for a simple desktop system? Also, I don't know how viable dual booting is, given that I manage my dotfiles almost entirely with home-manager, and I like to have secure boot.
It doesn't make any difference. Gentoo and NixOS have the same concept. They are holistic systems not designed for multiple permanent changes. I've used Gentoo, it's as much fun as building everything from FreeBSD ports. But some users install the OS to get work done, not to constantly tinker with the system, so now I choose NixOS.