I think that Adam Rippon definitely has "it".
(Oh, my, just realized how long this post is, sorry!)
I think it's the curls.
More seriously, I think Western and Eastern tastes are a little different. In the East, they often prefer men with delicate features, pale complexion, tender gestures, etc. That's why they especially love Johnny, and also Adam. Whereas in the West, there's this perpetual discussion of whether certain males make figure skating look less masculine to the general public.
A slight generalization, but I do think that the relative amount of "it" factor for the same skater is different in different countries due to cultural reasons, it's not like there's an absolute scale or anything.
As far as ladies go, I think Yu-na and Mao both have the "it" factor, Yu-na has more passion, Mao has more balletic elegance. Yu-na for me is like Stephane Lambiel among men, they may not hit the most elegant, balletic positions, but they skate with such intensity and commitment/belief in their program/choreography (Johnny made some statement like this about Lambiel in an interview, he said he admired Lambiel for that reason). I wish Yu-na would pick better music for this season, though, I liked her programs from 3 seasons ago much better, before she started working with Brian Orser (even though it's obvious that her jumps, skating skills, athleticism have all improved tremendously since then). The way she skates her programs, since Brian Orser, now seems so completely over-practiced to me, like every single gesture, facial expression is completely pre-programmed, and as such takes away from her emotional connection with the program and the audience. But that's just my opinion!
Among the US ladies, I'd say that Caroline has the most "it" factor, and Mirai has the second most. When all the ladies skate clean, Caroline gets the most standing ovations, and Mirai the second. Caroline's exhibitions are mesmerizing. She takes her time to wring all the emotional/musical nuances out of a piece, and she (as well as the audience) doesn't have to worry about rushing around the ice with speed. Ironically, when she's not worried about the competitive aspect, she skates faster and freer. I would *love* for Caroline to be coached by Brain Orser. He's done a great job in transforming Yu-na from a delicate, fragile little thing into a woman of athletic strength and beauty. Yu-na's speed, edging, quality of jumps have drastically improved under his guidance. I always thought that she wasn't as naturally gifted in her jumping ability as Mao, in terms of being a child prodigy and attempting super-naturally difficult jump elements (didn't Mao attempt two 3A's including one in combo, and a 3-3-3 at age 12 in Japanese National's?), I think Brian's coaching has *really* done her wonders, plus he seems really good at getting the most out of CoP with her abilities. So of course until Yu-na leaves Brian Orser (maybe after 2010 if she wins gold?), Caroline can't go to him, but maybe after? I'm sure the first thing he would do is make her do more cross-training, weight-lifting, running, pilates, etc. to make her stronger/faster (since that's what he did with Yu-na when she first went to him). And God knows that this is what Caroline desperately needs...
Mirai has natural grace/flexibility in her movement as Caroline does, and she has additional strength/athleticism/enthusiasm. But I think most of her successful programs so far, whether for competition or exhibition, have been ones in which she was very bubbly and kid-like. When she has tried to skate to mature, more serious music, it simply hasn't worked so well, her skating looks quite detached to the music, it's like her heart isn't in it -- I really do think that the bubbly/cheerful/funny music is what she can relate to the most, and that makes her most expressive on ice; perhaps with aging and maturity, she will grow emotionally as a person, and that'll allow her to show a broader range of personality on ice, too.