Tax Lien vs Note Investing

[David New]

I'm looking to start investing somewhat passively on the side of my normal day to day job. I've been intrigued by the idea of note investing and tax liens. Has anyone here have experience with both? What are the pros and cons to each? Does one offer better returns than another? Is one more suited to do part time than another one would? 

I have been looking at a handful of courses online for each but wanted to determine which route I would like to go first. Any feedback someone could give me would be appreciated.