I'd probably go with the 950 then, since its more future proof. With a more powerful doc, more ram, a better screen and camera, I guess you can't go wrong.
The 1520 is still a great phone. I didn't buy a 950/xl just because it's still running so great and picture is still superior to some new phones. Glance screen, double tap to wake, speaker, battery life, hardware buttons and it's screen size is hard to part with.