Nice article, even non-smart TV's are pretty diabolical.
My 5 year old samsung has a UI that is sluggish as hell. When selecting the input source there are no direct selections - you just have to keep prodding the button til you get the one you are after and it always reverts back to the built-in TV tuner when power cycled. If the source is offline then you cannot select it, so you have to go through all the sources again. There is no config option to set a default source on power up or to remove unwanted source that nicely clutter up the selection.
So my power up cycle for my PVR + TV is:
PVR on - wait til booted
press input source 5 times
This all takes about 20-30 seconds, if you goof then it can take a minute or two.
Whereas using a tablet is just a press of the power button, a swipe to unlock and then selecting the TV app - 5 seconds max.
And don't even get me started on my diabolical smart samsung DVD player, I have used the youtube function just once, the UI was slower than wading through a swimming pool full of treacle.