“At MHC, we conduct a lot of manual link audits. To do this, we gather links from as many sources as we can, including a number of third-party tools such as Ahrefs, Majestic, and Moz. It might seem like overkill to pull links from so many sources, but we have found that is the only way to get a comprehensive profile of the live links pointing to a site.
Crawling and discovering live links reliably is a very difficult task, and while the tools are much better than they used to be, none of them so far manage to get them all! For perspective, anecdotally, we would say that Ahrefs is perhaps the most “reliable,” but the number of domains listed in a full backlink profile is often 3 times as many as what Ahrefs will be reporting as the total number of backlinks to a site. So, in this case, “reliability” is quite a subjective concept!”