I think Ubuntu moved away from "polish for Linux distributions" some versions ago. This was the time they've started making their own user interface with Unity, they're own shop with I-don't-know-what-it's-called (App center ?) and their own online storage with Ubuntu one.
They make decisions you may like or may not like (moving the window controls to the left..) - but at least for me it was time to go - and I don't look back.
The fact that that has happened only gives more weight to the idea that they are in fact producing their own product instead of being a light packaging layer over what everyone else does.
They make decisions you may like or may not like (moving the window controls to the left..) - but at least for me it was time to go - and I don't look back.