You gotta have the big three: reliable GPS map app, a good music player, and better than meh cameras. If you can get those three things working, and working as well or better than comparable devices on iOS and Android, you've got a chance.
Right now, it's one out of three at best, based on the access I've had to a couple, and the reliability of calls/texts isn't exactly perfect either. I've yet to see one with a camera that isn't shit, and the music players I've seen can't hold a candle to even iOS's muddy, over filtered sound, even when they function well otherwise. I'm not even expecting high end sound, just sound that isn't fucked.
GPS though, that worked well enough the last time I had a device to test drive with. Not as feature rich, but still good enough for basic use.
Also ran into dropped calls and ghost texts disappearing, but that is as much on the carrier as the device.
They just aren't daily drivers yet, and I so badly want it to be.