Stevech: it doesn't actually need to copy the data; VMware will just start using a different hard disk file when a snaphot is created.
S4mb4: which country are you based? I got an email from a supplier in the uk saying that they had the 516 in stock. I'm dying to find out what they're like. I had decided on a qnap but these new netgear devices smash the price and support (5 years) of the qnap.
I received it yesterday.
I do not care for the OS 6 interface however i am loving the debian wheezy build they use underneath it. (to be fair i never used the web interface of the older nas either)
It seems very fast also. It built my new volume (6 - 2TB WD Reds) in about 4 hours. the Pro Business would have taken about 7 hours.
it saturates my LAN so i cannot test the write speeds.
scp from old nas to new nas (to move all my files) averages about 75MB/s (but like i said, i believe that is my switch and not the device)