Summary: I recommend using raw drives for initial install especially if you are having a problem. I have a few of these for quite a while and they are all good. I use Hitachi 4TB drives with good success. There is a new version the NSA 325 v2.
Pros: Fastest read / write in it's price range. Easy to set up and get running. Great for home media server and general back up storage. By the way, try deleting any Volumes / partitions and start with a raw drive.
Cons: Hard drive install and removal could be better. Other manufacturers are able to get the drives in and out without adding caddies or using a handle / pull tool for removal.
Summary: I did not purchase the ZyXEL NSA325 from Amazon. I got it on special from another online store. As others have said the instructions are lacking. I also had to look in the bays to see which way to install the drives. I threw a couple of two year old Toshiba in.
Summary: this NAS is small and powerful, configurable and reliable RAID1 (mirror) and NFS, mediaserver and even torrent client if you are familiar with linux you can do whatever you want with this system using ffp: [...] highly recommended
Summary: This NAS is quiet has many options and problably more than I can use. I use for simple file server and I am sure it won't be a problem to access from outside when I need to. Have a 2TB RED Western Digital and a Black 1 TB. Both perform good and I set them to spin down.
Summary: After some careful research on different NAS products out there I decided to pull the trigger and buy the NSA325 because it offered support for multiple transfer protocols (SMB, FTP, Bittorrent) as well as support for DLNA.
Summary: I was a bit nervous since the reviews were very mixed for NSA325. Also, when you buy drive from some vendor and enclosure from some other, if you run into a problem, it is not easy to find where the problem is.
Summary: i have been wanting to setup a media server/NAS in my house for sometime now and this NSA320 is doing exactly what i hoped it would. i will say that if you are not familiar with computers, networking, RAID, and servers then you have a bit of reading and learning to do first.