I think the majority of devices are 16:9 now, it's here to stay. One thing I really despise though is when they take a 4:3 TV show and crop it to 16:9, sometimes cutting the tops of heads off.
My office desktop PC monitor is 4:3, don't watch videos on that, it's for office work. So IMO the taller aspect ratio is better for me here, can see more of the Word documents and PPTs are 4:3 as well.