Of the three popular backlink reporting tools (Majestic, Moz, Ahrefs), Ahrefs provides the most useful link data. Even in other areas of SEO, Ahrefs seems to always keep their toolsets fresh. They continually add in useful tools and features that make other software suites less relevant. The most recent addition is their site audit tool which provides a beautiful visualization of technical site issues.
It depends on the size of your operation, but I think you could get just as much value out of the Mangools Suite. This is the group in charge of KWFinder. But you can also take advantage of their SERP watcher and LinkMiner, and SiteProfiler features since you have an established business. They aren't quite as powerful as Ahrefs, but they get you 90% of the way for about 50% of the cost.
If you are interested in having the SEO Audit Tool on your web platform, you can have a free seven day trial of it. By embedding this tool directly on your page, you can generate great leads from your users by seeing their websites or the websites they are interested in. From here, you can target a more specific audience and see great improvements in your conversion rates!
If you're okay with the pricing they offer – Ahrefs is the perfect solution for any content creators out there. You are able to step up your SEO game with data on number of backlinks as well as info on that particular site. But before you start using Ahrefs, try out what Google already offers first, maybe it will be enough for you in the beginning.
Now keep in mind that, based on their stated crawling guidelines, the stronger links from stronger sites tend to get crawled more frequently so the spammiest of the spammy link approaches might not get picked up on. For that level of deep research a historical report from Majestic SEO and a link status checker, like Advanced Link Manager, is likely a better bet.
The backlink index is one of the best too though at the time of writing, Moz has just improved their index. Regardless of index size, which theirs is large enough, the type of data they provide is the most useful. The broken links data is probably the most useful that isn't easily matched by other tools. Additionally, going back to the content explorer, you can find unlinked mentions, a feature that appears to have been removed in Moz's "new" tool (I may just not be able to find it).
We love the Intersecting Link Opportunity report, which helps us plan our link-earning strategy based on the semantic Web and relevancy. There really isn't a better way of finding industry websites to market with that could result in organic link wins. Our team has been using Ahrefs for as long as we can remember, mainly because it offers a higher volume of discovered links when weighed against similar tools.