AT&T has enjoyed being the dominant GSM carrier in the US for way too long. Verizon and Sprint don't even count because of their limited technology. T-Mobile can finally bring out all the beauty in the GSM version. Once they're re farmed they will have such a better network than AT&T. *LTE Advanced, with HSPA+ 42 to fall back on. (AT&T currently maxes their HSPA+ network out at 21mbps which is VERY congested. The iPhone 5 supports DC HSPA+. *Simultaneous voice and data the RIGHT WAY. AT&T currently throttles speeds during calls with very high pings. T-Mobile DOES NOT, and one can surf the web and talk the way it was suppose to be. Research this if you don't believe me. *TRULY unlimited data with no overages, no throttling, or metering. *Cheaper monthly service which benefits those who like to pay full price right away. *Visual Voicemail for T-Mobile Yeah that's just a few. I for one can't wait to ditch AT&T and hop on T-Mobile very soon with my unlocked iPhone 5.