What does the company do well? I've been using WP Engine for 6 years now. They're UX is and Cpanel are clear and modern. The 24 hour chat support and phone support is staffed by technical people and i haven't had an issue yet. Deploying sites and creating staging environment is super fast. When they realized that my hosting package might go over the teir i purchased, They were proactive and called 2 weeks ahead to notify our team and talk about solutions (either upgrade or be billed $1 for every 1,000 over our monthly use)
What does the company not do well? very little is wrong with WPengine. Sometimes it can be a bother to not have the customization of adding on extra things (like a client portal built outside of WP) but thats extremely small and rare. Also if you have custom SSL needs, the tier package that includes that is expensive for such a random issue.
What do you wish you had known about the company before using? Nothing really. Most Hosting Companies are straight forward with what you get.