I had one of these in my house for a week. I can confirm that the only main apps that worked were Amazon and Netflix, there were no iPlayer, ITV Player, 4oD, 5Demand at all. Worse than that, there were iPlayer apps, that simply brought up a screen saying not available. I emailed Samsung asking when these would be available and was told there was no date available for any of these.
One of my main chairs also sits off-axis and I can agree on the screen. Once off axis, the picture quality is terrible (I'm comparing vs. my 6/7 year old Panasonic plasma).
I returned it and got the 2014 model instead. Much better picture and all the apps work