Kahoot is an engaging and fun tool to have a review or a quick formative assessment. I see it being used in a lot of classrooms, but it is not always the best tool for the task, depending on the task.  While it is an easy tool to use to do that quick review or a form of formative assessment, it is not always going to be the best tool based on your needs and desires.  You have to be aware of what you are assessing and how you are going to use the information you gain from the assessment. 

Socrative has much better data tracking if you are going to be keeping track of the data for your students over a period of time.  Formative has a better variety of questions and even a question type that allows your students to draw out their answers, which would be a great use for in a math classroom.  Quizizz is very similar to Kahoot but has some added features and puts the questions on the student’s screen so they do not have to be looking up and helps those who may have vision issues, as well as allowing students to move at their own pace instead of all at once.  Google Forms is of course a powerful formative assessment tool that allows you to use a variety of question types, keep the data stored in either a spreadsheet or see the results quickly, and easily integrates into all of your other Google Apps.  

The thing is, you need to be aware of the purpose of using that tool and if that tool is truly the one you want to use.  If you are looking to use formative assessment to inform your instruction and to provide feedback to students, you have to think beyond just using a tool that is easy and fun.  While Kahoot can be used very effectively, many start using it only because it is an easy tool to use and thus keep using it even though they really should be using another tool once their needs change.  Once that tool does not allow you to meet your goals, you have to find another tool.  While the other tools may require a bit more learning and practice, they can better allow you to reach your own goals you have for using that tool.  If you are not conscious of your purpose and whether you are meeting your intended outcomes, you can not expect any tool to improve the learning.