I think it was pretty one-sided and the editing made it seem much closer than it really was. If it was close at all, the judges would've said something to the effect of "this was a very hard decision" or "this was a very close race". But there was none of that. Mei made one mediocre dish (the duck one), 2 good/superb dishes and the dish that pretty much sealed it - her dessert. I think the dry octopus thing was just clever editing - everyone seemed to really like the dish despite the octopus being a little chewy and thought it was beautifully presented. Gregory had 2 good/superb dishes (but neither got the same level of praise as Mei's dessert), a mediocre dish and of course the sugary carrot fish disaster. I think both chefs are equally talented but in different ways and it all came down to who made the most mistakes - and Gregory just made far worse mistakes than Mei.
