>>149257538Powergirl is older and from Earth-2.
She was trained by the golden age Superman into being a stoic and brave soldier. She is usually more aggressive and hot-headed than Supergirl.
Recently they've butchered Powergirl's characterization, making her into a lonely fish-out-of-water lesbian.
Basically the author of her recent stories wrote self-insert lesbian official fan fic where she fucks Powergirl. Kinda based, but it did ruin her character.
Supergirl for a while was the edgier, more troubled of the two. With her experience on Argo city and the destruction of her people being a major thrust of her character.
But as of late she's gone back to her silver age roots, and is just a teenage girl with teenage girl issues who is also a superhero.