Faerie Fire provides advantage to all combat rolls for the entire party. This is far too powerful for a first level spell, and very imbalancing. Why should an attacker get advantage simply because the defender is glowing? It shouldn't make the hit significantly easier.
Heat metal with no save - doing damage and giving disadvantage (despite concentration) is very potent.
Faerie Fire provides advantage to all combat rolls for the entire party. This is far too powerful for a first level spell, and very imbalancing. Why should an attacker get advantage simply because the defender is glowing? It shouldn't make the hit significantly easier.
At least there's a saving throw with Faerie Fire.
Unlike Heat Metal ... I'll just give that guy over there in metal armor disadvantage on all attacks for the rest of the combat and there's no save. Oh and have a little damage too!
Heat metal is very potent in the right circumstances, I agree. The limitation being that it's useless if the creatures you're facing don't have metal weapons or armor.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.