im new to these smartphone and straight talk. im getting a nexus 4 and want to use it with straight talk. i live in northen cali, humboldt county and att reception are horrible and i dont even think t-mobile works here. now my brother has a regular phone with straight talk and it works perfectly around my area. now from what ive been reading, if i get an att sim card to go with it i would get att service towers? but my question is would i get crap service? att doesnt even work on like 70% of my city area. i just want to be able to use my phone and get good service with occassional web browsing such as fantasy stats. are the sim cards used for data only or for both talking and data? i mainly it want to use my phone for unlimited talking and text. now i know a regular phone with straight talk works perfect but im not sure about these smart phones with sim cards in them. i just dont want to get crappy att tower services for talking on my phone. i just dont want to pay $150/mth for 2 smartphones on verizon so please help a newbie out here. thank you.