Been a long time since I posted!!!
I still have my DNS-343 and it's been running NFS for some time now.
It's mapped to 3 hosts running ESXi5 and I don't seem to have any speed issues whatsoever.
Starting up servers is fast and responsive, and I don't get any alerts from VMWare about network connectivity or missed heartbeats.
Oh, and this is just my home lab/network, which is why I'm using Cheap and Cheerful DLink
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I should also mention I'm on 1.04b03