Summary: We used these with a large number of Macs for support - working in IT, these things are a godsend. Not only does it work very fast as a thunderbolt target device, but the connector for the disk is just a SATA connector - so you can use the thunderbolt drive sled as an impromptu Thunderbolt disk...
Seems flaky, may have blown out Thunderbolt port, doesn't work smoothly with my system
2 December 2014
Summary: Bought this for a MBP but it wouldn't mount when I plugged it in. Turned out the Thunderbolt port was bad, but I had never used the port before so I'm not sure if it was working prior to plugging in the drive.
Summary: We noticed a tendency for the unit to send the disconnect error message (we use Mac) after the computer wakes. Most USB storage (i.e., thumb drives) don't do that. It became annoying and my wife stopped using it. On the plus side, it packs a lot of storage in a small space!
Summary: I have a couple of external Western Digital drives that interface with Firewire 800. Bought this Seagate specifically because of the capacity and the Thunderbolt connection. I use the application SuperDuper for backup purposes and this drive, thus far, works perfectly.