Not so well:
When the Sea is Rising Red by Cat Hellisen - There's kind of a love triangle but it doesn't feel fleshed out at all. She seems to hate the first guy that's a potential love interest and then becomes close to him extremely fast. The second kind of love interest is a vampire. Felicita is drawn to the vampire Jannik but is also repulsed by him at the same time. They seem to work better as friends and it seems like she is going to manipulate him for her personal gain.
The Mortal Instruments series - (too many incesty moments and then you could tell who she'd end up with the whole time at least at the last book I read of the series.)
Icons by Margaret Stohl - The love triangle that kind of wanes and ebbs is interesting yes but I really don’t want a lot more of it. Also I’m pretty much very against the choice she makes at the end. I just can’t get over how the powers of one of the guys could be influencing the whole situation plus you should only be able to seemingly betray people once a story at most
Works So Well:
Throne of Glass series - now this is how you write a love triangle. The love triangle is actually well done and makes sense as in I’m not a hundred percent sure right away who she might pick. I’m a fan of Chaol more than Dorian but there are legitimate reasons why she might end up with either guy. She has some pretty intense chemistry with both Dorian and Chaol. Who knows she might end up being her own woman and picking neither guy
Shatter Me series - this was such an awesome and surprising love triangle. It’s the first time I’ve completely switched who I was a fan of by the end I really wanted to punch one of the love interests in the face/tell him to grow up.