I suppose the balanced way to evaluate the scenario is to select key determinants and compare them side by side, e.g. compare performance (graphics and responsiveness), ergonomics (phone size and design), camera quality, hardware eligibility for updates, battery life, etc. In my opinion, the 1520 wins in all of these criteria (though maybe not by a far cry), except in camera and a bit in ergonomics (since some may find the 1520 "too" large). That being said, the 1020 can be considered a "slight" downgrade from the 1520, but definitely not a "bad" phone at all.
