How to apply data binning on reviews data?
You can bin on Len of the data. you can also bin on Keywords you are interested in. You can use Countvectorizer with YellowBricks library to arrive at Frequency Plot. You can tokenize into N grams and find the frequencies. Depends on your problem statement that you are trying to solve. You can do Sentiment Analysis on each of the reviews and bin them into positive negative and neutral. There are many ways you can think off.

I hope this helps.