From my long experience building high-end NAS servers and struggling with Macs, generally using 10GigE connections:
Using SMB, the typical Mac pro can't do much better than 150/200MB/s to/from the NAS.
The very same Mac booted on Windows via Boot Camp reads/writes at 1GB/s on the same NAS.
Back to MacOS, using either NFS or AFP the Mac easily reads/writes at 1GB/s on the NAS.
The SMB implementation of MacOS is utterly broken, and has been for ages. NFS works fine generally, but some programs such as Quicktime pro and more annoyingly, the Finder sometimes have trouble with it.
Unfortunately, the fastest and most reliable option by a large margin still is AFP, using Netatalk. If you take care of cleaning regularly the CNID database, it works like a charm. I have many customers using servers with hundreds of TB of storage with AFP and it just works.
