Until you need them, none. They sort of become self evident and you'll know when you're in the market for them. For now, don't waste time on premature optimization.
And now you read the release notes with dread as you witness more and more functionality being dropped because they choose not to maintain it. Luckily there is FreeBSD
My experience with NFS over the years has taught me to avoid it. Yes, it mostly works. And then every once a while you have a client that either panics or hangs. Despite the versions of Linux, BSD, Solaris, Windows changing over the decades. The server end is usually a lot more stable. But that's of little to no comfort to know that yes, other clients are fine.
However, if you can tolerate client side failure then go for it.
Best of the bad options doesn't make it a good option. It's far from reliable and one of the most common reasons I encounter for deadlocked Linux systems. Well, to be fair, it also hangs a fair share of BSDs and sometimes even a Solaris. If at all possible, I'd suggest avoiding it.