Summary: I have a Fall 2013 entry level, 21" iMac. iMac is a non-fusion model with the standard 5200 rpm hard drive. The iMac was purchased as an "upgrade" to replace a retiring 2008 iMac but the beach ball cursor appeared so often that it didn't feel like much of an upgrade. So thinking the hard drive was the problem, and that I had a spare Samsung 128GB SSD laying around, I bought this to see if it would help.
Summary: I have a MacBook Pro 15" with a USB 3 connection on it. This definitely sped up transfer rates and amazingly enough this little thing hooks right up and works even better with a bare 2.5 drive.
Summary: This is a little pricey for what it is, but I think I was expecting too much from it. I use the drive for my Time Machine backups, swapping in 1 of the 2 Seagate GoFlex drives I have, storing the alternate off-site. What I've found is that I can close the lid of the laptop and hibernate without issue with the drives in the standard USB configuration, but when using the adapter and the Thunderbolt port the drives are "unsafely" ejected when doing the same.
Summary: This is my second FreeAgent. Love them, they are killer for ease of use and dependability. The first one I still carry to work every day and have been for over 5 years. Works great. Excellent value.