I don't know about that device, but I have the Elgato Systems EyeTV Hybrid. It just plugs right into the USB drive and the software does the rest.
www.elgato.com
They have several devices to choose from. The Eye TV250 Plus was 50$ more and actually did all the compression supposedly taking the strain off the main CPU. Honestly, I am running a Aluminum iMac 24" 2.4 G with 4GB of ram now. and unless it's compacting or exporting the processor doesn't slow that much. I thought upping the RAM would solve the problem, but it's truly a CPU issue. I am not a power user by trade so I can live with the slowdown. If I were to be doing this for a living and needed to be editing another clip whilst two others were compacting... I'd either get the EyeTV 250 or invest in a Mac Pro.
All in all the eye TV is simple, easy to use, effective and reasonably priced. Just like Macs!
MacDad