I am mildly surprised that Marcel and Ilan won this round, to go through to the final head to head. Though I must admit that at this point I don't really care much about the outcome since I don't care much about any of the four semi-finalists. The whole Elia accusing Marcel of 'cheating' sequence (with zero shown support from Ilan or Sam) was so awkward I'd rather forget it.
The food was quite interesting, but I've never been to Hawaii. It's definitely on my list of must-go-to-someday places, especially since there are strong ties to Japanese culture there. (Besides, I often get mistaken for being from Hawaii...not sure why!) But I've never really had Hawaiian food, so I don't know what poi or any of the other foods that the contestants were supposed to emulate, or evoke, in their dishes are like. So I felt like a blind person trying to appreciate colors when looking at the dishes for the challenge. Once again, this points out the disadvantages of a food or cooking show contest. We can only trust what the judges say about what they are eating.
One thing I really objected to was the comment/view expressed, especially by Tom Colicchio, that Sam didn't do much because he didn't 'cook' anything. Does cooking mean you have to heat food in some way? That's ridiculous. "Cooking" with acid is a valid process. Putting ingredients together is a valid process. It shows a bias against cuisines that do not heat all of their food. It may have been a nitpicking detail they used as an excuse to differentiate the contestants, but it was frankly silly. Is foaming up xanthum gum and pineapple juice 'cooking'? I guess the judges thought so, since Marcel passed.
The number people that actually care about what is going on in the higher echelons of haute cuisine are probably just a tiny fraction of the population. And the number of those who have actually gone to a 'molecular gastronomy' restaurant are a small fraction of that (mainly because they are mostly located in a few cities, and they are all prohibitively expensive). It's safe to assume that way, way more people watch the Top Chef show from the comfort of their sofas.
So it's likely that Marcel has, for better or worse, introduced this 'molecular gastronomy' (which I put in quotes since the practitioners of this say we aren't to call it that anymore) stuff to more Americans than all the 'real' chefs who are proponents of this kind of cooking combined. Because his interpersonal skills (at least in front of a camera) and presentational skills (ditto) are so horrible, this is probably a bad thing for the movement. He's not a master of the methods, his judgement is not always right, and the foam has become a running joke. The methodology of 'molecular gastronomy' seems weird, sci-fi-ish and eccentric in any case to the casual viewer. It would have done the movement a ton of good if well-liked Sam for instance had been the resident MGist of the season. I'm not a wholehearted fan of the movement myself (I've noted before  the similarities with the methods used and the industrial food manufacturing methods employed by big corporations, and wondered what the big deal really is) but it's a shame if one rather immature young man can do this. (In contrast, the recent BBC series starring Heston Blumenthal  was a much better intro to the movement, from an acknowledged master. I hope it makes it over to BBC America someday so people in the U.S. can compare.) Not that the producers of Top Chef care anything about educating the public, I'm sure.
So...who's going to win? The logical choice might be Ilan, who despite some weak moments has mostly survived unscathed by too much controversy. But then, not-liked Jeffrey did win the last season of Project Runway...