I suppose you'll see the largest image on the ipad since the app on there can go full screen. So far, i only got it for the sport channels and at R36 per month, that's still a pretty good deal, especially if you don't have a full DSTV sub going (like me).
You definitely won't be using this all the time, the other channels are pretty crappy and very light on content. We're talking 2-4 hours of content per channel on a 24hr loop. E-News and CNN is ok to catch up on some news, but i have not found the other channels worth watching (except for Supersport 1,2,3 which is most likely this device's main selling point) , even Mnet Series is basically just Jerry Springer every hour *sigh*.
Oh and i mentioned it elsewhere, you can not output the stream via HDMI from the ipad to your tv (most likely the same thing with iphone)....the app will block it, so don't buy this for your iphone/ipad thinking you are going to throw it up on the big screen. So on a tablet like the ipad with a 9.8" display it's fine to use at work or at home and watch from the couch, but on a phone i'd only get this if i am traveling alot during the sport events and want to catch some of it on the move.