Western Digital My Cloud Ex4 Device?

I had thought I posted a question here a day or two ago but I seem to be mistaken.  I wanted to get the take of those here on this device, how it compares to the Sentinel, what the OS is, and how it will compare for backing up Windows devices.  Also, trying to figure out if it would back up to keep vault as does the Sentinel.

http://www.wd.com/en/products/products.aspx?id=1170