To me this is kind of like asking, "Which game is better Shovel Knight or Super Mario Bros 3?"  Shovel Knight is a tribute to classic gaming, while Mario 3 actually is one of the best games from classic gaming.  The tribute is good but not as good as the original thing.

This is not meant as a disrespect to Guns N Roses.  In the late 80's Rock had become incredibly stale with mostly just hair metal bands, and GNR got Rock back to its roots which was sorely needed at the time.  But Led Zeppelin and Stairway to Heaven represent the best of those roots.  (Clearly Stairway is my pick.)