Ironically, the only hardware feature that the Buffalo box has and the Netgear doesn't is the two hard drives. If you order a 500GB ReadyNAS Duo, the company ships it with a single preinstalled 500GB drive rather than two 250GB drives. Unless you specifically request a pair of 250GBs, you'll get one. Our model came with a single 500GB Western Digital SATA. That's a little weird, since most of the Netgear's benefits require dual drives.

Still, if you've got the green, adding another drive is easy enough given the box's hot-swap capability—and the process is made even easier by the proprietary X-RAID technology, which lets users plug in a secondary hard drive of any size as long as its capacity is equal to or greater than that of the original. Slide the second drive in and it will start chugging away, no extra effort required. The X-RAID technology saves you from rebuilding the array manually, so you don't need to store your data elsewhere while inserting the new drive.

Those USB ports also make the device more flexible than its primary rival from Buffalo. Where the latter can accept only hard drives, the Netgear handles additional USB hard drives and flash drives, printers, and even a Netgear USB wireless adapter, so you can convert your ReadyNAS Duo into a wireless device. Netgear currently does not have a USB Wireless-802.11n adapter, but if your wireless router is from Netgear, it will likely support the company's Super G implementation. That's Netgear's technology for using two Wireless-G radios in tandem to provide up to 108-megabit-per-second throughput, which should be enough to stream even HD media content. Note, however, that I didn't test that.

Getting started with the ReadyNAS Duo is exactly like configuring the ReadyNAS NV+: It all starts with installing the included RAIDar software (the CD has versions for Windows, Mac, and Linux systems) on at least one PC on the network. RAID will scan the network for any ReadyNAS products, so it will pick up any other ReadyNAS product you might have installed. Most likely, though, you'll see only one ReadyNAS; just click on it and then hit the Setup button at the bottom of the screen. This kicks off the Web-based management console, which is where you'll spend the rest of your configuration time.
 

Much as with to the NV+, once you've run through the setup wizard, the ReadyNAS Duo will show up in your other PC's Network Neighborhood or Finder views. You'll still need to install RAID if you want to fully manage the ReadyNAS, but for basic back-and-forth copying or drive mapping, your other clients are good to go.

Backing up clients to the NAS requires backup software, which Netgear has included (NTI Shadow) on the Install CD. You can also use Windows' built-in backup software or some other third-party package if you prefer. The ReadyNAS Duo, unlike Windows Home Server, requires third-party software if you want an image backup of a network drive, and you can't make one when doing a backup of the ReadyNAS itself.

Where the ReadyNAS Duo begins to differ from its larger cousin is in the home media-sharing department. The ReadyNAS NV+ has some basic media-serving abilities, and they're refined in the newer device. For one, in addition to being able to access your files using FTP or Secure FTP over the Web, the NAS actually has default templates that let you build a photo-sharing Web site directly from your photo folders. The box also has an iTunes server and a media server that's compatible with the Microsoft Xbox 360, the Sony PlayStation 3, the Logitech Squeezebox, and any UPnP AV-enabled network media device.

The ReadyNAS Duo's performance was another nail in the coffin of the Buffalo LinkStation Pro Duo. The ReadyNAS Duo, with its 256MB of memory, wasn't quite as fast as the ReadyNAS NV+, but it was still fast. On Gigabit Ethernet read tests, the box averaged 24.6 megabytes per second when working with 32MB files, falling to 11.31 MBps using 1GB files. Compare to the Buffalo's 14.7 MBps and 9.2 MBps, respectively. On write tests, the Netgear device managed 17.53 MBps with 32MB files and 13.7 MBps transferring 1GB files. That's noticeably slower than its more hardware-muscled precursor, but it's lightning-fast compared with the Buffalo LinkStation Pro Duo, which averaged only 10.1 MBps with 32MB files and 8.92 MBps with 1GB files.

In the battle of the dual-drive home NAS appliances, the Netgear ReadyNAS Duo is a clear winner over the current implementation of the Buffalo LinkStation Pro Duo. In fact, the latter seems suited much more to simply sharing small and medium-size files on a typical small-business network than to undertaking tasks such as media serving in the home. The only area where the Buffalo wins is on price, but considering the difference in features, I think most home users are better off opting for the ReadyNAS Duo. It simply has more features oriented toward home users, as well as better performance and more hardware flexibility.