I love my Vitamix for smoothies but stopped using it because it was frankly too much of a pain when making 1 or 2 servings.  My least favorite part of my Vitamix overall is having to use the Tamper tool.  With the personal cup adapter, it's a breeze and I love it!  My only wish is that the 'adapter' was simpler / smaller; it's basically like using 1/2 of a blender container and the bulk makes it somewhat clumsy.