Empties are rare for me. Usually I'll buy a product, and start using a different one a week later. This is mostly because I either didn't like the product, or I thought it was OK, but I could find better. So to get to finish up a product, for me, usually means it was a winner!
As even finishing ONE product rarely happens, I figured as I'd actually finished 4 products I'd let you know my thoughts on them all.