I'd be sticking with the thumb as she can control when it goes in and out....and you wont be getting up in the middle of the night to put it back in.

Like a few others have said, it only causes problems when it's used long term. Chuck a band-aid over it when you want her to stop....worked for my freind.

I too hate the look of a dummy in a cute little baby's mouth.....ugh. Mind you, Caty sometimes has one in.