FWIW, NetApps were generally pretty solid, and they should have no problem keeping in sync across datacenters. You pay handsomely for the privilege though.

Failover, latency, and so on are something you need to think about independently of what transfer protocol you use. NFS may present its own challenges with all the different extensions and flags, but that's true of any mature technology.

That said, live code updates probably aren't a very good idea anyway, for exactly the reasons you mention. Those are the reasons you were right at the time, not any inherent deficiencies on the NFS protocol.