A differentiator explanation only works if buyers believe the differences are neutral or good. Hence the question of whether consumers actually use Samsung software.

There would still be intense brand rivalry. Not everyone can tell pepsi and coke apart by taste.

True, but what if, although I do think the analogy kind of falls apart there, Coke was allowed to dictate any change to the recipe? That's the situation Samsung would be in if they relied on 'stock' Android. Google would have a significant advantage simply because they control both the device and the OS (the latter IMO more important), and Samsung would only be able to compete by device.

And that's even assuming that Google doesn't 'leverage' its ability to control both software and hardware.

It's enough to know that they taste different, even if you don't notice it yourself. If nobody could tell Pepsi and Coke apart without the label, that would become public knowledge pretty quickly and defeat the branding.

But most know that the store brands are usually re-labelled coke or pepsi, usually without much tweaking to the recipe, if any. But they still buy the main brand.

on the other hand I'm on the fence for the new galaxy a3, but having a non standard android to be updated only when samsung says so bothers me

but I do understand I'm likely not their reference target