I have a short list of publishers I like to promote. Russell Brunson is one that comes to mind. His products convert better for me than many other big names.
So if Russell has a new product, I am inclined to promote it even if I am not that impressed with it because he has proven to know better than I what sells.
Other than that I am usually interested in tools and products that help my list members succeed.
I also prefer to promote where I get an ad swap in return.