There is certainly no parameter to decide that if its overrated or not but there are definitely some problems in the website. 

After I saw your question visited the website (https://steemwhales.com) and decided to take a look. I soon realized that the website database hasn't been updated for the last nine months, which not only makes it obsolete but unreliable as well. During the last nine months a lot of things have changed - a whole bull market has gone by and we have been in the bear market for more than last six months. 

A lot of accounts on Steemit have virtually disappeared and a lot of new ones have been created. Steemwhales have none of this updated and added to their database.