I took Manuel's course at it was one of the best Houdini courses I've taken. https://www.cgmasteracademy.com/courses/16-intro-to-fx-using-houdini Great content and the attention to detail from the instructor was top notch. There is over 40 hours of content so it's a lot to go through but it's well worth it. I plan on taking Kieth's class in the Fall. I don't know if I need the entire program but at this rate, I might end up doing it. I am looking forward to taking the fluids ones once it opens as well.
Let me know which course you sign up for, I might see you in class.