I have owned a Vitamix blender for years and I've blended down cane sugar to make confectioners sugar when I ran out, spices for making my own sausage mix, smoothies, you name it.  I loved it so well I bought one for each of my kids.  I bought the personal cup adapter about a month ago because my husband and I like to add different things to our smoothies.  We both love it for the convenience of making personal smoothies and the fact that you could take it with you if needed.  I have read reviews stating that this adapter leaks, but that is no true.  If you make sure to screw it on correctly and tightly it does not leak, and , just like the Vitamix, it easily rinses clean if you clean it immediately and don't let it sit on the counter and dry out. You have to be smarter than your equipment as my husband always says. (I did not receive this product for free in order to review it.  I bought it after seeing a demonstration at Costco).