NVidia borks my installation sometimes. Then my stupidity to choose the non-dkms beta driver from the AUR. But all in all, my non-NVidia-devices (server, workstation and laptop) run fine on arch testing, updated every time I use one of those devices.
Kinda. One of the Linux "wrappers" (I'm a bit tired and can't think of the correct term here, bear with me) that lets you utilize some Linux utilities on Windows, maybe it was mingw or cygwin, actually uses pacman as their package manager IIRC.