I can only speak from personal experience, so don't take this as true for everybody. But for me, NFS has always been a colossal pain to use. The server has to

I can only speak from personal experience, so don't take this as true for everybody. But for me, NFS has always been a colossal pain to use. The server has to run in kernel-space. Shares have to be enumerated in /etc. There are a couple of userspace options, but I've never been able to make them work reliably. Once I do get it working, it hangs all the time for no easy-to-debug reason. Also it needs multiple ports to be open, and it expects UID and GID to be the same on client and server. CIFS has its problems for sure. But it's been pretty straightforward for me every time I've had to use it. If I was trying to set up a production-line machine to flash Linux-based devices, I'd choose CIFS every time because it's so much less hassle. And now that it's rootfs-capable, I just might be able to do it.