I am planning to buy one of these, but I would like to know what people's experiences are with it
I would like to run some VMs from it using NFS but also stream video through my xbox.
Does anyone know if this device can easily handle this, or do I need to go up to a TS-419 for example?
This NAS only operates at 800MHz, and it is an ARM rather than Atom based, so it is probably not suitable for VM's. It can probably handle streaming video to your Xbox, however, again the 800MHz CPU speed might present challenges.
I am using a TS-419P+ (1.6GHz CPU), and I am successfully streaming videos to all my Xboxes, Boxee Boxes, and XBMC-based PC's without issue. I am playing with VirtualBox on my Laptop for VM use, but I store all my VDI's on my Laptop rather than my NAS, as I tend to create large virtual disks for my VM's, and wouldn't want to load them across the network, even at full 1Gbps speeds.
Choosing the right NAS can be a frustrating exercise... Have you checked out the QNAP 4-Bay Comparison Chart
This chart compares their various 4-Bay NAS units, including transfer rates, CPU speeds etc. I was initially looking at the TS-412 myself, but after looking at this chart, I eventually decided to pony up the additional cash to purchase the TS-419P+ instead. (QNAP released the TS-419P-II three weeks after I purchased the TS-419P+, or I would have chosen it instead).
It was financially painful to purchase this NAS and 4 * 2TB drives all at once, but I didn't want to go through the pain of RAID migration later, so I simply waited until I could afford to purchase everything at once. I eventually want to upgrade to 4 * 4TB drives, but due to cost this upgrade will take a while.
If loading VM's across your network is important to you, you might want to choose an Atom rather than an ARM based NAS unit.