Nix: The Purely Functional Package Manager

It (Nix) provides a much more pleasant experience on Linux/NixOS itself.

On OS X, like right now, after switching to El Capitan, you begin to see the disadvantages.

In fact any major change in some packages, require a lot of digging around and most of the time, the solutions are not at all obvious, and mostly undocumented properly.

Also, when you do find a workaround, you will still have to compromise and compile everything from source, waiting for the binary cache (hosted by the project) to catch-up.

The flexibility, and cross-platform nature of Nix, is something that's difficult to resist though (regardless of the philosophy of the project).