How I Use It
When teachers ask how to put student cellphones to use in the classroom, this is my go-to tool. [See http://www.thedigitalcore.org/strategy-3-immediate-feedback-and-dynamic-instruction.html].
This allows students to respond to open-ended discussion prompts so that everyone gets a chance to formulate their statement before the teacher simply calls on two students, letting everyone off the hook for even thinking.
The main review is correct: the quiz module is limited. That is by design. It's only intended for short, instant feedback, formative tasks. For an array of quizzing features, Socrative (or Infuse Learning) is the right tool to use.
This is an amazing tool. Engage the whole class. Know what kids are going to say before you call on them (by previewing their written responses). Keep the discussion focused on your learning objectives and know where gaps in understanding exist. Put all of the computing power in your classroom (cellphones) to good use. There are an endless number of ways to deploy Go Soapbox.