I’m not sure you can watch 4OD on a big telly – only pads and computers I think. I cannot airplay it via Apple TV from my iPad – it comes up with a message telling me you cannot broadcast 4OD on a TV. I’ve a Samsung and 2 Panasonic SMART TV’s in the house, both have iPlayer but neither has 4OD.
My standard answer is get a Panasonic at whatever your budget, its my preferred brand. I’ve had a few now and they have always been great. I deviated with a Samsung TV for my bedroom (not the kids!) due to its thinness and i’m not that impressed with it. Its fine for a secondary bedroom TV, but nowhere near as good as the similarly priced same sized (32″) Panasonic TV I got for the in-laws.