I was buying my girlfriend of 1 year her first real earrings (real gemstone, etc...). She didn't know what she wanted, but she's had some problems with her ears reacting poorly to silver, and even gold (allergic?). A jeweler recommended platinum, and she tried on a quarter carot pair (that the store had on sale for $499). The quarter carot fit well, and looked nice, but I certainly didn't want to go smaller. I found the 1/3 here for a little over half, and decided to try them. They looked quite similar to the ones in the store, but I certainly liked the price. Well, she loved them, and the look great on her.
Do yourself a favor and have her try on a similar pair for size at a store so you can get an idea of the size and its appropriateness.
As for negatives...I don't like that they come without certification papers, and as everyone else said, the box is ugly.
Finally, buy these. Buy a small earring box somewhere else for a couple of bucks, and give a gift that she'll love.