As the three characters cost 595,000 credits to purchase, this pack saves ~25% credits. Along with the Gotham City Pack, it is one of the two temporary packs that contains three characters that do not require any unlocks and can be purchased separately at the store.
For new players, while the Red Son Pack, Femme Fatale Pack and Tag Team Pack are all clearly superior, the Metropolis Pack can be passable if lacking other options. Krypto Lex Luthor's team max health increase scales well with Superman's high base health and further augments Doomsday's strong self-heal through his passive - Doomsday is a very good beginner card as well as he can heal himself a lot without using gear. With Doomsday as the main damage dealer, Superman as the tank and Lex Luthor supporting and power draining, this could be a fairly effective team.