Does anyone use the Amazon Prime Dash Buttons? How do they work? Can you select your favorite item in each brand, or is it all preset? what about more than one item per brand? How does the price compare to subscribe and save?

I am interested in the Tide button and the Amazon Elements buttons, but I want to know if I can get my Tide free and clear pods, and the Amazon Elements Sensitive wipes.

What are your experiences with the buttons?