ChromeStats gives you a quick break down of review trends over time, number of reviews with a given rating, and the average ratings from recent reviews.
You can scroll down to access a list of recent reviews on an extension via ChromeStats and filter by review ratings.
Looking at user reviews trends will help you determine if an extension has improved or gotten worse recently.
Free and Personal plan users will only have access to the most recent 25 reviews. Upgrade your plan to access up to 100 reviews.
You can also click on the reviewer's name to find all reviews done by a given reviewer. Reviewer analysis will give you further insights into the reviewer, allowing you to quickly identify spammy / bot reviewer.