Majestic SEO (Majestic Site Explorer) is the largest updated link index base in the world and one of the top link analysis tools. Functionally this backlink checker it is quite similar to Ahrefs and Moz Open Site Explorer. The tools’ priority metrics are Trust Flow and Citation Flow (shown in the upper box of the Summary page). For high-quality link building you must indicate donors that are as authoritative in your particular niche as possible, and this info is exactly what Majestic gives you.