I wholeheartedly agree with Oscilla. Mao is already evenly matched with Yu-Na. She just needs more mental composure. If she messes up on a jump, she needs to move on & refocus (don't leave out a jump, lol). I think Yu-Na is emotionally more mature in that respect & it shows in the way she's carried herself in competition and in interviews. Yu-Na is also a greater performer than Mao in the way she can connect to an audience through her facial expressions, her conviction, etc.
But overall artistry I would give to Mao with regards to skating posture, flow over the ice, positions, pointed toes, smoother transitions, etc. Yu-Na is a far greater technician imo with the jumps- greater speed, distance, & more precise edge entry. Her jumps do show signs of fatigue in the end of her long programs though because she isn't a "timing" jumper like Mao. Mao has better air postion in her jumps than Yu-Na. Yu-Na hooks her left arm to garner speed in her jumps (exception on axels), whereas Mao is tight w/beautiful ankle extension. Yu-Na has cleaner landings. Yu-Na has better spins than Mao, more centered with far greater speed. Mao has better spirals. I mean the list can go on & on. Point is, they're both great. If one of them falters, then the other will win.