which galaxy note 5 to buy to work on At&t?

I've been looking online to buy a galaxy note 5 to work on At&t, I don't want to buy an At&t model because it can't be root and the Tmobile one needs to be activate it for at least 40 days with their service in order to unlock it.... (kinda lame), so , I'm between buying these 2 models SM-N920W8 or SM-N920C ?

which one would you guys recomend I heard some guy bought the International and his signal was not a great as the At&t version? any feedback, recomendation or advice?

Thanks for your advice
Jesse