While I have neither, I do have a BlendTec. Like many others, I blanched at the thought of spending close to $400 on a blender. However, I could never make a decent green smoothie with my Oester along with other blended drinks. After a lot of research I decided to bite the bullet (no pun intended), and pickup the Blendtec as it was on sale at my local Costco. It worked so well that it was the major turning point for me to turn vegan. I have pockets in my gums that make it impossible to drink smoothies made with raspberries, blackberries or any hard seeded fruit. With the BlendTec, I run it on "Whole Juice," then "Smoothie." No seeds! The Blendtec is an essential part of my daily diet. If the Blendtec died today, I'd probably get a VitaMix because they are available all the time at Costco. As far as a comparison between the two, it only boils down to price. Which one is available at the better price. The are both great appliances and produce the same great results. Any debate between the two is like debating Mac vs Pc, Ford vs Chevy. In other words...too much to do about nothing.