More luxurious, gown-looking.
Both looks good on her but I have a thing for the green one.

I like both of them

The Green one makes it more unique than the other DP dresses and it's more special than the other gowns.

The Blue one just looks good all around. :)

The blue one is cute but I just LUV her green dress!

This, because it comes at the end of the movie, most of the oficcial costumes of DP leave at the end of the movie

this is already her official DP dress

cause the other one kinda hideous -__-, this one is more elegant.
though it's Lotti's dress, so i don't think it's the official one.

The other one is nice, but it's not her dress.. well I know Belle's isn't hers but Tiana has her own green one so, it's iconic aswell.

This one. I like how she looks in green. Besides we have already a princess with a blue dress (technically we have 2).

I like the blue one, but green is her color (frogs?) and Cinderella's blue/silver one is very known, and I like this one a lot! actually is my favorite dress ever

I'd say this one, even though I personally like the blue one better...I just think people associate her with this dress better.

Both look nice on Tiana but I think her official dress should be the green one because we already have 2 princesses wearing blue in the line-up. And another reason is because the blue one belongs to Charlotte.

Because this dress is just Godly, it really connects with the fact that she was a frog and spent the majority of her film in the bayou. It's really different from all of the other princess's dresses, and I like the fact that it's green, it makes it stand out from the others and shows off colours other than pink and blue.

I haven't seen the movie, but still just looking at them, I like the blue one way better.