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'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.
SEOptimer is a free SEO Audit Tool that will perform a detailed SEO Analysis across 100 website data points, and provide clear and actionable recommendations for steps you can take to improve your online presence and ultimately rank better in Search Engine Results. SEOptimer is ideal for website owners, website designers and digital agencies who want to improve their own sites or theirs of their clients.
One of the things that AHrefs is best at is helping with a content marketing strategy. Though it's best known as a backlink index (which it's great at and I'll get into that), coming up with good content ideas is one of the things I get the most use out of it with using the content explorer. I find articles that do well for the topics I want to target and it's clear what already resonates with your audience which is powerful.
What would be the purpose of/reason for moving back to a different url? If its been a few years, I’d leave it alone unless you watched everything decline since moving to the main url. Moving the forum to a new url now would probably be a bit chaotic, not only for your main url but for the forum itself…. Only reason I could imagine myself moving the forum in this scenario would be if all those links were really awful and unrelated to the url it currently sits on…
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.