Ahrefs boasts the best link database among any system out there. It does most everything -- link monitoring, alerts, calculated metrics, the richest clickstream blend out there, and much more. Its UI is cluttered in a good way and the company has quick and polite support. And Tim Soulo -- the public face of Ahrefs -- has done a ton of good for the SEO community.
Ahrefs is incredibly comprehensive and straight forward. From keyword discovery to site audits I use ahrefs for all my SEO needs. It's the first SEO program I was introduced to when starting me SEM management career and has proven to be the best time and time again. I've used their competitors liker moz, SEM rush, and a couple other services- none of which have come close to stacking up.
There are numerous SEO tools out in the market, however, if link building is the topic at hand, then I honestly think that using Ahrefs is enough. Starting with the dashboard – just input the details of your site and your keywords, then it will give your potential competitors. It’s easy to use and it also has one of the best features for finding broken links, curating skyscraper articles, and link reclamation.
The thing that I liked the best about Ahrefs is that it contains a huge database of backlinks when I've checked my own website and my competitor's websites. This has allowed me to dig deeper and find out their exact linkbuilding and SEO strategies. Ahref contains a lot of tools and features that will make the life of an SEO professional or webmaster who wants more search engine traffic a lot easier. One of these features is the batch analysis feature. Basically, instead of entering your competitor's backlinks one at a time you could actually enter it once. This allows you to quickly check on the SEO metrics for a lot of competitor URLs in just one click.