Everyone has a bad customer service story about every company but that does not mean T-Moblie has a customer service infrastructure problem.
Recently, I switched from Verizon to T-Moblie when bought a Nexus 5 on day one. The SIM card I had ordered would not automatically activate which was not a surprise as the Nexus 5 was not in their system (they were not offering it yet). I also wanted their unadvertised $30 plan technically only available to Walmart and their online phone buyers. One call, everything was setup with no problems and no hassles. Verizon is the definition of hassles from my experience.
Recently, I switched from Verizon to T-Moblie when bought a Nexus 5 on day one. The SIM card I had ordered would not automatically activate which was not a surprise as the Nexus 5 was not in their system (they were not offering it yet). I also wanted their unadvertised $30 plan technically only available to Walmart and their online phone buyers. One call, everything was setup with no problems and no hassles. Verizon is the definition of hassles from my experience.