I use Kahoot as well. I find that it is a great resource for review prior to an assessment. The students love it and most get very competitive with it. This leads to a good deal of student comprehension of the material that is in the Kahoot.
I have found that Kahoots that I create are more effective for my class than ones that I have received from someone else. When the Kahoot is put together by an outside source it often doesn't quite fit what we are doing in class.