Both of these learning management systems have their issues. Neither should be considered for a production online course website for different reasons. Sensei is not really being developed and LearnPress is not coded well. A quick glance at their reviews is enough to scare anyone away. I recommend you instead consider LifterLMS if you are wanting a free LMS and LearnDash of you want a paid one.
There are many concerns I have with this plugin for using it in a serious environment. If you look at the reviews people have left, there are many red flags there. Concerns with it breaking websites, not following proper coding standards, and limited to no support. I do question their business model and if there will be enough revenue for them to continue developement.
Sensei does not integrate well with 99% of WordPress themes. So if you are not a developer/coder, you will have a tough time getting it to work right with your theme. Also, it requires WooCommerce and several expensive extensions to function properly. This makes the total cost 3x higher per year.
