I have done a review of Authoritas on video also which may be helpful.
The product is perfect for me but may not suit everybody

https://www.youtube.com/watch?v=pLn0OH20mok

Getting Started.
I found the learning curve to be easy and I had no problems setting up. The instructions are clear and once you understand how the UX is you will have no issues.
If you watch my video above I will show you the keyword tools which I found confusing at first but soon got the hang of it. There are two sets, one is called market keywords and these are for your backlink profile and the others are for normal rank tracking

What I love the most
The tool has so much in-depth data for your projects however the items that really sold me are
1. the "intention" percentages for each keyword, (I made a major change for one of my clients today when I learned the keyword was transactional and not informational)
2. The snippet, image and ask question tracking ...GOLD!
3. The pure rank versus true rank (i.e videos , images, etc ) It may be the same as above bit this is my first day with it!

Speed.
The tool loads fast and the data is fast to propagate. The FAQ section takes a few minutes but it totally worthwhile waiting for.

Competition
UNLIMITED analysis of your competitors, repeat unlimited !. This alone is worth the entry fee as you can interrogate your competitors with one click to find backlinks, rankings, domain strength etc etc .

Dashboard.
I love the dashboard configuration and having the widgets all in one place gives great reporting and the ability to track competitors quickly plus see any movements in keywords, backlinks etc

Support
The support is great, very fast on the first day with my newbie questions and all answered politely and with references to some amazing training. I have watched their webinars today and some great content in their too.

This is a very advanced SEO tool and a steal for the price but would still suit a beginner for the basics so grab it. I am a huge fan.

The keyword tool only relates to a project as far as I can see (please correct me if I am wrong) so I found I had to use my other tool for general research on other topics but I could set up a project I guess and do it that way. But that is not a deal breaker for me