My Take
I like it more than other assessment tool because Formative not only has the multiple choice option or true or false option, but it has other options such as short answer and show work. I can see how much students understanding from the lesson by looking at their work. I can upload pictures or hints or screen shots. I usually upload screen shot from the part of lesson as a hint for students.
How I Use It
I sometimes used it as a formative assessment and sometimes I used for homework. I believe providing student immediately feedback about their work is one of effective ways of teaching. Giving homework is a good practice for the lesson of the day, but grading it will take time. Thus, I assigned meaningful questions about the lesson of the day for students to do on Formative. I can quickly check to see how are the students learning from the day.