Samba vs NFS has had little impact on performance these days. Standard Blu-Ray disks require only 54mbps MAX. With 3D BD, I think the max is 72mbps (but not 100% sure on the 3D BD one). In fact as of 2011, Microsoft actually started contributing code to Samba.
If you check the benchmarks, the performance difference for both reading and writing seems to be negligible for large files. I haven't run a test myself though honestly though to see if that holds for streaming. We actually use SMB for our showroom (without any problems).
But, we have come across many routers (and switches) with issues honestly. In particular, early 802.11ac routers seemed to have serious bugs. Also, we've tested "Gigabit" switches such as the cheap Linksys ones and they also had issues. The WD devices also may not provide sufficient throughput (on your computer, try streaming a file off them and check the performance)
If you have Sonos, assume network loops though (better routers simply make the loops it creates less obvious).