This unit is quite heavy, as you'd expect from a metal-cased drive with two HDDs inside, but that's actually a good thing. It sits nicely on the desk and seems to be pretty solidly built. I've got two cats, so that's an important point for me. The speeds and functionality are amazing. I also love the design of this drive. I'm really pleased with it.
I have set up my LaCie as RAID 1 4TB mirrored storage. It was a snap to set up using the Apple disc utility and it hasn't missed a lick yet. I use it for my iTunes library and I am very satisfied with the product.
I'm shooting a documentary at the moment and a lot of it uses archival footage. I've been using this drive to edit video and to backup this project (that's many hours of video in total). I switched it to Raid1, which was rather straightforward. The speeds are excellent. The drive is also good for running high resolution video renders. It's also nice that Thunderbolt cable is included with the package.