These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ensemble Darkhorse: Power Girl is an Ensemble Darkhorse in the greater DCU; fans love her and many feel she's underused.
Internet Backdraft: Some fans weren't happy that Power Girl, who existed originally as the Earth-2 counterpart to Supergirl in that they were both cousins to Superman and had superpowers, now started off in the new Earth-2 as explicitly as a direct counterpart to Supergirl, having started off her superheroic career as Supergirl.
And there's the costume design...
And that she's way less heroic than before the reboot...Let's just say that fans of Power Girl are not big fans of World's Finest in general.
Les Yay: In the New 52 her friendship with the Earth 2 Huntress/Helena Wayne is full of this.
Back in her solo series, there was a lot of Les Yay between Kara/Power Girl and Atlee/Terra, with a bit of Precocious Crush subtext on the part of the latter. There was a bit of Foe Yay between Kara and Satanna, though in more of a Combat Sadomasochist way.
Magnificent Bastard: Subverted with her recurring foe Desaad. He's an Evil Genius who sees himself as a brilliant chessmaster and future ruler of Apokolips. In reality he's a Dirty Coward who, while sometimes dangerous, tends to get dragged off to a horrible fate by his genuinely competent boss Darkseid.
Narm Charm: The famous boob window has become such a big part of her character and charm that both fans and writers violently object whenever DC tries to get rid of it.
They Changed It, Now It Sucks: World's Finest is this incarnate; make the totally heroic Power Girl a dodgy Anti-Hero, change her costume and remove the most famous aspects of said costume, and team her up with Huntress when Power Girl has always been a solo hero... it's like DC wanted to use a different character entirely before deciding to slap Power Girl's name onto it.