Galaxy S4 is working great with appRadio. Can't unchain it since it is a work phone which is kind of lame but I would assume anything in the compatability list would be great and even better if you can root and use appRadio unchained.
I'm hoping they announce android radio firmware for the 8000 like the brand new 8100. Android radio is pretty good looking.
CarPlay does look more polished so if an apple phone is an option for you it might not be a bad choice if one of your main factors is connecting to your NEX