Returning an X cost spell from your graveyard to hand is neat, but it seems like more often than not, you're only going to get two bonus mana from that card you returned, even in a deck dedicated to X spells
P/T Number 4 Language English Legal Formats Alchemy, Brawl, Commander, Competitive Brawl, Historic, Legacy, Modern, Pioneer, Standard, Timeless, Vintage Rulings (6/6/2025) Aerith Gainsborough's second ability triggers just once for each life-gaining event, whether it's 1 life from Al Bhed Salvagers or 3 life from Balamb T-Rexaur
In order to decide which product is best for you, the first obvious aspect to consider is the size
Both cards want to see permanents repeatedly leaving your battlefield and reward you with scaling +X/+0 bonuses to all your creatures