I like the fact that this plugin works within my own website. I’m not sending course participants somewhere else to access the course content. If you’re confident with Wordpress as a platform you're likely to be able to figure out how to use MemberPress fairly well. The annual fee is reasonable and it stays the same regardless of how many people you have take your course. That’s great for economy of scale (less great if you don’t have very many paying customers). For payments it integrates well with Stripe and PayPal.
There is an add-on plugin called Affiliate Royale that it works with if you would like to have affiliates refer to you.
It can be daunting building everything from scratch. You need good design and WordPress knowledge.
People who are savvy with WordPress.
If you’d like the freedom to make your course exactly how you design it this is a great plugin for you. Course content is entirely built from scratch. When you use this plugin your course starts as a blank Wordpress page.