how well does WP handle streaming transfer from wifi to 3/4G?

My Nexus 4 with Android v4.4.2 still can't do it (and that's really annoying)

for example, I'm listening to Spotify at my house and walk away, when I lose wifi it just won't transfer the stream to my cellular signal, the music stream drops and I have to screw with the phone to get it back

see my googleplex post here:

http://www.theverge.com/2014/3/14/5510892/4-4-2-and-i-still-cant-walk-away-from-my-wifi-when-streaming-music