C'mon guys this is easily Anakin. Anakin was always a bitch. Remember the whole "He's holding me back!!!!" He was a bitch even before Padme died. He CAUSED Padme's death because of what an ******* he was.
Obito on the other hand was an amazing good hearted person who turned corrupted due to the loss of a loved one. See the difference here? Anakin being a bitch caused Padme's death, but Rin's death caused Obito to become a bitch.
In the end, neither turned out well and have their faults since they both made their wrong choices, but I give Obito more credit since he was victimized, rather than being the one to cause his own downfall.