The UI seems nice on the video, but I think you need to use it yourself to have a good opinion. I wouldn't be surprised if you often go back to the running application screen while scolling up the application grid. Also, they kept some swipe gestures, but not the animations that made you understand it right away what you're doing. Here, when he swipes, there isn't any card following your finger out of the screen, like on the N9. It may be due to a Nokia patent, but I hope they will come up with a more intuite way. I also think they lack a proper identity. When you see a squircle, immediately you think Harmattan/Symbian/Nokia. There, their icons have different shapes and styles, there is no coherence, and it could be any Android frontend. And it seems to me that many of the new concepts found in Sailfish are also in the new Blackberry OS, so I hope they won't fight each other with some patents. I am also a bit worried that there is no status bar. I like seeing all the time my battery state, my network and having a notification icon for messages or updates whatever the application I am using at the moment. It's good that they want to do something different, but they should be careful not to loose in usability. I have a lot of hopes for Jolla, that's why I point out the negative aspects. But there are also a good number of positive ones. Android compatibility is a huuuge advantage over Harmattan. I also like a lot the idea of the UI adapting to the main colours of the wallpaper. The interactive tiles seems like a good idea to me, even if I'd like to use it myself to have a better idea. They just presented the current state of their new OS, I am sure it will be improved over time. And I'm looking forward to being able to install that on my N9 for testing.