Sans Digital MOBILEstor MS2UT
The Sans Digital MOBILEstor MS2UT is designed for two instead of four hard drives, but given that there are 750 GB hard drives available while the first 1 TB models are already on the horizon this doesn't have to be a disadvantage. The device supports RAID 0 and RAID 1 modes, and it has to be configured using the front panel on the device. The display only shows hard drive status.
We found a mute button on the device as well, which is helpful to turn off the acoustical alarm in case of a drive malfunction. But be careful: Once it was disabled you have to turn it back on manually, or it won't warn you at all. A button that would trigger the mute function for a limited time would certainly have been better.
Sans Digital provides software, which can be used to monitor the device and to change its settings. The software isn't really comprehensive, but it is smart enough to send error emails in case of a drive malfunction.
Both fans rotate at over 6,000 RPM, and although we used two 7,200 RPM 400 GB Western Digital hard drives, we're absolutely sure that even two WD Raptors at 10,000 RPM would never overheat even at half the rotation speed. As with the easyRAID device, the Sans Digital box is clearly too noisy for an office environment. Most people will only be happy with this product if it is locked away in a server room, where noise doesn't matter as much.