Out of the two ducklings, which one is your favorite?
I have experienced them both. They both live in my second town now.
They are both cute. If I had to judge them by design, I would pick Molly. She looks the most natural.
You can't really judge them on personality, because they both say the same things.
I've never experienced Molly. But Deena was really sweet when I had her in Cityfolk. I never really grew attached to her though. If I had to base purely on design I would have to go with Molly. She looks a lot like the classic female duck you would see in real life.