Hi,
I did a bit in SEO. Used Moz, Semrush, Ahrefs and Mangools keyword tools. Also have Frase, Webtexttool (Textmetrics now), TopicMojo and Marketrush and SpeedPPC.

Postpace is really usefull if you need to write some new content. The topic report from Postpace gives you overview and insights in HOW your competitors are using the keywords. But before I start writing, I allways do some keyword research. For keyword research I'm using other (premium) keyword tools, if you are looking for that you could take a look at SpeedPPC. That's an Google Ads tool but it has a keyword tool with premium source built in. Premium keyword tools have more reliable keyword volumes!

TopicMojo and Marketrush I use for getting the supporting keywords and as input for my articles. It also shows what you need to do to be able to compete more on a topic.

For writing the content I prefer using Frase and finally editing it in Textmetrics. That end result is how it would be 'theoretically correct'. But if you want to look at the content 'competitively' for things like keyword frequency, wordcount and readability you could use the content audit from Postpace.

So Postpace is a nice addition to my SEO toolset. Happy with it. Well done!