The enclosure with no drives is about $150. This thing is rock solid aluminum construction I expect from OWC. When not thrashing from having gigs of data dumped on it the thing is whisper quiet. It did rattle some as any external does when being hammered with a 4GB transfer of audio files.
The dual 500GB drive 32MB cache unit they sent goes for about $380. Basically, if you have your own sata drives you can save cash by getting just the enclosure. I own a different OWC enclosure that uses the same Oxford chipset. I have not run into any compatibility or performance issues with that chipset on any of my computers, Mac or Windows.
The drive provides firewire 400, firewire 800 and USB 2.0 interfaces. All three worked as expected in my tests.
In a nutshell, at firewire 800 I could copy 1GB/minute to the unit. That stayed consistent from just copying a chunk of files to cloning my internal drive to it using carbon copy cloner. Cloning my internal drive took under three hours. I was able to boot from and run my iMac from the drive. Just have the cloned drive hooked via firewire and hold the Option key while powering on your mac. This will let you choose which bootable drive to start from.
Below, you can download the PDF of my xbench comparison of my internal drive, my WD MyBook hooked up via firewire 400, the Guardian at fw400, then again fw800 and lastly attached to an airport extreme via usb2.0 as a shared drive. Looking at the numbers will show that the unit on fw800 is competitive with my iMac’s internal Sata drive. You can actually see the benefit of having dual mirrored drives when looking at the uncached read numbers. There is a slight boost on the read throughput. The numbers for the unit attached as a shared network drive show just how much the network slows things down. This is great for small files or backups you seldom touch. If you want to work with large files on a frequent basis I recommend firewire. USB works well for Time Machine backups.
If you need a drive enclosure that is quiet, solid construction and uses a quality chipset then you cannot beat this unit. Add in that you gain protection for your data from the hardware RAID 1 mirroring. Don’t settle for the mediocre units you get at the local consumer electronics stores if you can order this instead.