As for smartphones: the maximum width of those screens is dictated by the average size of a human’s palm. If you make the screens wider than 2.5", for most people it will be uncomfortable to operate the phone with one hand. Look at the Galaxy Note[1] (which is 3.3" wide), it’s practically impossible to use with one hand.
[1] http://www.engadget.com/gallery/samsung-galaxy-note-ii-hands...
Is that a fact or an opinion?
>> 4:3 is terrible for watching HD videos or browsing websites -- all of which are made with a 16:9 screen in mind.
I also prefer watching videos in a widescreen format.. however, I prefer browsing the web in a portrait view. More often than not, the "side" of the web pages are used for navigation and ads. When it happens, I usually zoom on the content in the middle and read that in a portrait view.
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I think your opinion is valid but not the way you express it. It sounds very aggressive and also comes out like if it was a hard fact. (Which is not, it's your opinion)
If their ad had shown a VivoTab and an iPad side-by-side playing a widescreen movie, I wouldn't have had a problem with it. (In fact I would've agreed with them that the VivoTab is probably the better device for viewing widescreen movies).
Instead their ad claims that the VivoTab is "larger", "lighter", etc all of which are objectively incorrect.
Of course the VivoTab can only play scaled down 1080p video. That probably does not matter to most people, but I really don't think Microsoft wants to go down that road.