After I upgraded my Macbook Pro to a 1TB SSD, I had my old 512 GB drive, but I couldn't use it, so it just sat in an antistatic bag for over a year. When I saw this, I ordered it right away, and am happy to be able to use my old drive as a secondary disk.
The only bad thing about it is that it's speeds are nowhere near the drive when it is installed in the computer - With the drive in the computer, I see speeds of 600-860 MB/s R/W, with it in the envoy pro, I see speeds of 200-360MB/s R/W. This is with the drive about half full, it will get much slower if you let it get more than 90% full.
Other than the speed issues, the enclosure works well. It's milled from aluminum and matches the look and feel of my macbook pro very well. It is bootable, so I'll probably partition it and use it as a bootcamp / mac os upgrade test disk.
It would have been great to have this in 2014 when I upgraded my SSD, as in order to transfer my data from my old SSD to my new one, I had to back up my old SSD to an external drive and then restore it to the new SSD, with this enclosure, it would have been much easier and faster.