How I Use It
My students have always been very competitive. I have used Kahoots in a wide variety of ways. I've used it for everything from a pre-assessment to an informal review to a formal assessment. I like that you can collect and keep the data once the task is done. It has worked very well for keeping my students engaged. From my experience, they tend to put forth more effort because it is a competition than they would if it was a typical pencil/paper practice session.
I think Kahoots work great and tend to keep the kids focused and engaged. I have created my own and used ones that were already created by other teachers. I always careful review any that I use that I don't personally create to make sure the content is correct and appropriate since anyone can create an account and make the Kahoots.