Here is my observation,
Mar - may have been the most prepared on the issues thrown to him, this may have been because TV5 have not properly controlled the timer. Most of the time has been consumed to defend tuwid na daan and still he have not set himself apart to Noynoy's legacy. He also showed his lack of emotional control and anger management during pre-debate debacle sounding like he is a sour loser and on the debate itself when the three others are ganging up on him.
Grace - very composed and answered most question on point. she also shown aggressiveness in dealing with mar and binay, but shown her lack of experience on coco levy fund issue, dilg's jurisdiction on pdea and in answering the specific question of duterte. It seems she is like a recording of chiz escudero and could be caught by impromptu specific questions.
Duterte - have not provided specific approach in dealing with issues such as handling criminality and climate risk reduction. But have shown his character on the pre-debate debacle. It also seems that other presidentiables are afraid to throw questions at him, aside from heated arguments with mar on davao drug issue which duterte did not even bother to deny. In my opinion this may be a strategy of other presidentiables not to let duterte open his mouth since he is already charismatic to people, thus lessens his air time.
Binay - ..... putang ina. panira ng araw... may goebbels goebbels pang nalalaman nuknukan naman ng sinungaling. nevertheless, he has a point on stating that he is yet to be presumed guilty, simply because he did not face the accusations head on. pero putangina talaga, paimportante amputangina.