Originally Posted by Salamafet
I'm waiting for Ubuntu and Firefox OS on my phone.
What's the best ?
Depends. It seems Firefox OS is meant more for low-end phones (though I've recently read that they want to make high-end phones with it), and it's Gingerbread-esque interface reflects that. Basically, we don't know, but as it is right now you probably wouldn't be reaching the X+'s full potential with it.
That being said, Ubuntu Touch is still highly in beta (and even after it is officially "ready" at the end of the month it'll have issues), but developers are planning to make it a high-end mobile OS experience...hence why they are building it on top of CM 10.1. So if you're patient, I think Ubuntu Touch will be the way to go.