The most beautiful legendary is clearly Heatran. ;w; [/jkjk]
... There's only one thing that really bothers me about the new legendaries, and that would be the cloudman trio things. They look almost completely identical. I thought Sinnoh's lake trio was a bit much, but god these things are just... no. Not to mention they don't really look like Pokemon. I know everyone throws that around about the 5th gen 'Mons but... Honestly, they're spotted men riding on clouds. Fff.
I do adore the Fighting trio though. They're definitely gonna be fun. And I'm gradually growing to like the Ice/Dragon more and more. Reshi and Zekky were awesome when I first saw them and they still are.
The rest are just sorta eh. They didn't stand out much to me. That may change later. :/