She’s the T-Mobile Girl, a.k.a. Carly Foulkes, and last time you saw her she was dressed in pink and using a cheerful approach to sell the carrier’s services. The darker image in the new ad spots–dubbed the “alter ego” campaign—are part of T-Mobile’s effort to rebrand itself as more “edgy” and in the process attract more customers.

T-Mobile wants to make a point about 4G speeds. In a hotly contested battle, AT&T, Sprint, Verizon, and T-Mobile are wooing new customers with the promise of data speeds around 5-20Mbps or higher. Yet, claiming to offer 4G and delivering that speed are different things. No carrier has consistently provided super-fast speeds in every town, especially if you connect in a busy area or far from the tower. We know this to be true from the hotly contested debates on our forums.

But, as to marketing specifically, how do you think T-Mobile is doing? Do you like the new look, or would you rather Carly went back to her spring pink dress?