I love the toolset, these guys are always building something new into the suite.
I have been using the tool starting around 2008 :)
The entire staff is amazing, I have been able to work with them at live events including seminars as well as their amazing online workshops keeping me up to date on things other marketers are doing with their websites.
If you manage a website, it is totally worth the money, especially with their Audit Tools helping you to identify areas of your website that may need improvement helping your overall technical SEO.
I feel like I am always learning with weekly online seminars, especially since they work with some of the Top SEO Influencers all over the world.
(Tons of SMART People)
Another great resource would be their SEO Academy where they have free online digital marketing courses & exams to help increase your skills from beginner to advanced.
One of my other favorite tools would be the Domain Overview Report allowing you to type in any domain including your competition giving you a ton of very insightful information. Review collected by and hosted on G2.com.