It's a good option for those with the right current smart devices and if screen size isn't a major concern.
There's FAQ info about it here: http://now.dstv.com/Home/Help
It would work concurrently;
You can register a maximum of four devices to your single DStv Premium PVR subscription. A maximum of two simultaneous viewing streams across your registered devices is permitted.
This means that you can either: be streaming two live TV channels OR stream two Catch Up videos OR stream one live TV channel and one Catch Up video.
But don't know if one can stream the same one live channel on the two different devices.
And I don't know if 2 x Desktop Players can also be registered, but presume if so they would then also work concurrently.