How I Use It
I enjoy using Socrative as a group based quiz (due to some Internet issues in my classroom). There is a "Space Race" function which shows each group's progress, which promotes competition while allowing groups to answer questions at their own pace.
This is a very flexible system, it allows quizzes to be student navigated (students can move forward and backwards through questions) or student led (students choose timing and receive immediate feedback on answer but can only move forward through questions) or teacher led (teachers dictates the speed of the questions, and students still receive personal feedback).
I have also found the range of response types to be valuable, responses can be multiple choice (2+ choices, allowing true/false or large number of options) but better for me is short answer responses. This can include numbers for Maths Questions or paragraphs for longer responses.
Additionally I suggest reviewing garden.socrative.com to find shared quizzes prepared by other teachers from around the world.