Latias she's cuter and can shapeshift into a human.

Ooh. This is a tough one. I'm going to have to go with Latios, because of how he tried so hard to protect everyone around him in the movie. <3

Latios. I have seen no movies and so my knowledge is based only on the games, but he's blue. :P

Why isn't there a both choice? =/

I don't knooooow ;_; I could say Latias, cause she was rather adorable in Pokemon Heroes...

But then there's Latios.... And Luster Purge <3

Well, I have to say that Latias is better. When it comes to competitve battles, Latios is better but if we're gonna talk about appearance, I'm pretty sure Latias would win.