The main advantage of the 300 PRC is not the cartridge but the chamber. Less slop means better accuracy. If any 30 caliber magnum was cut to the same specs and twist and put in a magnum action using the same bullets it would do as well.

But if starting from scratch, the PRC would be a fine choice.

No, the edge is not obsolete as you cannot shoot a 300 gr bullet from a PRC.