There's a, not insurmountable, learning curve for both Sailfish and Ubuntu Touch.

Quirky isn't necessarily better if you're trying to woo users who just want a familiar experience without learning new paradigms.

The lack of a back button in Firefox OS annoyed me! Instead of pressing a section at the bottom right of the screen with one's thumb, one had to 'click' on a web toolbar button all the way near the top left of the screen.

It's not that "gestures aren’t that difficult to get used to", it is more do they offer anything more than the tried and true?