This is currently the lowest price for a 2TB portable (2.5") drive. The physical drive inside the case is a Samsung, and can be used to upgrade the existing storage on a PS4.
The drive is USB 3.0 compatible, and is formatted for Windows. To use on Xbox One as additional storage, just plug it into one of the USB ports. The console will re-format the drive for use automatically.
For Mac, just connect and re-format. Voila.
£67.90 as of 16:31 on 22/01/2015