Like most things, it is subjective. I know that for some keywords I target the top 3 SERP shows really low DR/UR sites/pages but when you look deeper with other products the sites have hidden PBN's which are blocking AHREFS bot. So, I have learnt the hard way to make sure you do a thorough competitor analysis before dropping any cash. As others have said, AHREFS can be influenced both ways. I use Semrush to help me find hidden PBN's and I am sure that others will tell you better tools/methods to find them.