I admit to being puzzled initially by the many options available in the Data Download System. (You can access this system once you have become a registered user). Through trial and error I eventually figured out what I needed and how all the files work together. Below is a high-level summary of the main points about these downloads.
First a disclaimer. I choose the title of this post to reflect how I think others view these data products. These are not, in fact, competing data products, nor are they alternatives to one another. I view these data products as complementary, each with individual strengths and weaknesses, but ultimately a powerful data analysis resource when combined. Below I briefly describe the difference between the two data products and outline the pros and cons of using each (though my ultimate recommendation is to combine the two data products for a “pros-only” data set).