What does the company do well? I've tested lot of SEO platforms and Moz is the best program to manage the ranking of your webpage. You can easily view all the evolution using friendly graphs. It helps you to design your SEO strategy giving some ideas to improve your keywords. On the other hand, the blog is really awesome, you can learn about SEO from beginner to advance levels watching videos.
What does the company not do well? In my opinion, premium plans are a bit expensive, but it's reasonable because Moz helps you to increase your performance and if you know how to use it properly, you can win more money. So I assume the cost as an inversion.
What do you wish you had known about the company before using? Moz is a powerful tool that I would have liked to discover before. I'm sure that if I would have had the possibility to try it for free for 1 month I would finally buy a plan even before.