They’ll show you information like how many external links the site has, the number of Facebook and Google+ shares, estimated visits per month, and its page authority. All of this is valuable intel that can give you insight into where your page could potentially rank against them, without needing to do more research with a separate tool or on another page.
A service like BrightEdge comes with the biggest costs associated, but its SaaS solution for SEO covers many areas inside of a single ecosystem, including the ability to explore keyword data. This may be a benefit for agencies that wish to reduce redundancies across vendors, but eventually, it is likely that the need for a second tool will present itself as talent and effort levels increase inside of your SEO department.
I just have the free version right now so I don't know all that the pro one can do. But even the free version has A LOT of tools you can use, I haven't even figured them all out yet. But one that I have used is their Content Optimizer. You can take a new or existing content piece of yours, and compare it to one of your competitor's pieces on a similar topic, and see where you might be lacking based on the keywords that are used in each piece.
Most people who use the Google’s auto complete feature to generate keywords that they include in their blog title or page find Soovle to be a very useful tool. This tool moves the auto complete feature a step forward by getting inputs from several sources like Amazon, Yahoo, Wikipedia, Bing apart from Google itself. This assists the user to generate keywords that drive online traffic in a better way. The default is usually set to Google but you can switch to the other options at your own will and view how the outcome keeps on changing. You can experiment with a broad range of keywords by running them through a specialized tool such as the keyword inspector as a way of extracting value that will boost your sales on Amazon.