The original (this one) has a softer lip color, and her green eyes have a fun "sparkling" effect around the pupil. Also, her hair is styled in a true bouffant ponytail: it's cut short at the base of the pony, to give it extra fullness and lie thinner and wispier at the top.
You might also notice differences in her ribbon choker, her pink (rather than black) shoes, and the feather hair trim. She's just lovely--and one of the reasons I started my Steffie collection.
See more photos of this lovely doll on Flickr.