Hard to say. It's an original series, so we don't know much about it yet.
What we know so far is that it's a magical girl original series done by SHAFT and headed up by an all-star team.
Director: Akiyuki Shinbo (Several of SHAFT's successful series like Bakemonogatari, Arakawa, SZS, Hidamari, etc.)
Writer: Gen Urobuchi (Fate/Zero, Saya no Uta)
Original Character Designs: Ume Aoki (Hidamari Sketch)
Character Design Adaption: Takahiro Kishida (Baccano!)
Music: Yuki Kajiura (.hack, Baccano!, Kara no Kyoukai)
The cast is also high-profile.
Madoka Kaname - Aoi Yūki
Homura Akemi - Chiwa Saitō
Sayaka Miki - Eri Kitamura
Mami Tomoe - Kaori Mizuhashi
Kyubey - Emiri Katō
Even the supporting cast consists of the likes of Ryōko Shintani and Yūko Gotō.
The opening theme is performed by ClariS (OreImo OP) and the ending theme is performed by Kalafina (Kara no Kyoukai, Sora no Woto).
It's somewhat of a standard magical girl series at first glance, but the first episode has already proven that it's going to be very different from what people expect out of the genre and the staff has already stated that there is a "grotesque" element to it. (This shouldn't be terribly surprising given the writer.) People are speculating it'll be a deconstruction of the genre.
The first episode has been very promising and it only stands to get better after all of the plot and character setup is out of the way. We're looking at a pretty dark magical girl series in coming weeks.