I really enjoyed Midna, sadly it was one of the few things I enjoyed about TP - I found it to be too much of a OoT clone. I like her personality, it reminds me a lot of Tatl in Majora. Both just use you for their own purposes and don't even try to hide it - the both take advantage of a vulnerable Link (wolf/deku) and exploit him for favors. It makes them jaded and more dynamic as characters overall. Lots of people were more than a little disappointed with her transformation into her 'princess' form at the end, but I found it to be fitting. It makes the whole game a sort of redemption quest for her - not only is she finding the light for herself, but for her people as well. I have a feeling, that even though she shattered the link between worlds, the Twilight Realm was left better off because she quested with Link and got to understand Zelda's heart.