While I'd encourage you to try the software that comes with a NAS unit, you're not married to any proprietary or pre-supplied backup software. You can choose among anything that's available that recognizes network drives and find something you like from that superset rather than settle for what you're handed.
For this roundup, I looked at three recent NAS units: Promise Technology's SmartStor NS2300N, Iomega's StorCenter ix2 and MicroNet Technology's MaxNAS. Somewhere among these three could be the NAS unit you've been desperately seeking -- even if you haven't realized it yet.
How we tested
All of the PCs and the NAS devices used in these tests were connected via a hardwired Ethernet network using a Linksys EG800W switch. I decided against a Wi-Fi connection because, in the past, I've suffered through a number of anomalies only to find out at the end that it was the wireless connection at the bottom of them all. While Wi-Fi is more than suitable for typical file storage needs, it's difficult to recommend Wi-Fi for multiple streaming events, especially in the already crowded 2.5-GHz band.
To test performance, I timed how long it took to copy a 934MB file from the PC to each NAS unit and to copy the file back to the PC. Then I repeated the procedure while streaming a video from the NAS box to a different PC.
Since each of these NAS units also had media and/or iTunes "server" capabilities, I streamed multiple songs or videos from the devices to several PCs on the network. At one point, I had four different videos streaming off a unit into four different PCs. In no case was there any evidence of lagging or hiccupping or anything else that might be impeding the media experience.
Iomega StorCenter ix2 Network Storage
Iomega was once known for its Bernoulli Box and Zip drive -- two devices that offered higher-storage capacities to those unwilling or unable to use tape drives. Today, the company offers the StorCenter ix2, an NAS box available in 1TB (US$299) and 2TB (US$479) versions.
Iomega's pricing is very competitive with Promise's. The difference is that while Promise offers a hollow NAS box with a "Bring Your Own Disk" feature to keep pricing low, Iomega's StorCenter is populated and ready to run when you unbox it. However, while this makes the StorCenter very simple for the technological newbie, it's a feature that may not appeal to everyone.