Mr. Wallingford turned me on to the Quiz feature in Google Forms. If you are looking for a way to give quick feedback to students give this a try as an alternative to Flubaroo.
Getting started with Quizzes in Google Forms is simple. Open a new form from Google Drive and click on settings.
Choose the Quizzes tab and follow the prompts.
It appears that while Flubaroo might be a bit more powerful, Google Forms is simpler. Mr. Wallingford also told me that he found it was more accurate in grading student responses.
Give it a try and send feedback.