I've been using SEO Powersuite for a long time now. I love all of them, but Website Auditor and Rank Tracker are my go-to tools. I was really surprised to see them here, considering they are not a startup at all but a well-established software already. Hopefully, AS will bring the whole suite to us somehow, I'll jump in head first!
Website Auditor gives very accurate audit with an actionable to-do list of what to improve. The best thing is that they have databases for A LOT of countries. I mean AN AWFUL LOT!!! Think about small island countries where you don't even have hope that SEranking or SERPstat are going to cover anytime soon. The software is constantly updated too, I think I have new updates every few days.
This is the inarguably awesome deal, full stop. I hope nobody misses it!