This would be a red flag in my book. If they can't respond to simple questions then what is their customer support like?
I've tried a simple NAS drive in the middle of the year, from a different company, and was displeased with the performance. I ended up just connecting the drive to a old box that I loaded server on just to get faster results. This little experience left sour grapes in my mouth as far as economical NAS devices go. When I look at a NAS appliance, I look at how it is made. To me, it should be along the same lines as a simple file server and performance should mimick this. Check what OS it uses, processing power, etc..
The plus to this device, that you show, is it's ability for RAID 5 and hot swap capabilities. This would be a must for any critical data retention and redundancy. However if you want a cheap, inexpensive file server, you could basically get a old box with WinXP loaded with a bunch of drives and throw it on your LAN. You don't even need to connect a monitor or keyboard to it. You can administer it with RDC.
