Honestly, I, myself am a big fan of Edelgard but the thing I really like is that people either love her or hate her and there rarely seems to be an inbetween.
And I think that just goes to show how well she was written. Discussions about her fly around everywhere, where for other characters, there is barely any. Well written characters will always have people talking, no matter what side they are on and I think that just goes to show stuff about the quality of Three Houses in general.
Also, her crush on the professor is really endearing when she's not busy wagering war.