Bests & Worsts Reviews from Amazon

I liked this product until I encountered two major problems caused by the product design. I used the jar to make cashew butter (raw cashew without adding anything else, so it's very dry and hard to mix at the start but after several runs, oil from cashew comes out to make a smooth texture). The 1st jar lasted for about nine months and then one day, while I was making cashew butter, there was loud noise and smoke came out from the blender, and I found hundreds of tiny black pieces of unknown material got into the cashew butter. I threw away all the butter. Later on when I was cleaning the jar, I found water leaking from the bottom of the jar. The next day I called Blendtec customer service and told the rep what happened; the rep appeared familiar with this issue. The rep asked me to throw away the old jar and ordered me a replacement one. I received the replacement jar in about a week. Good customer service. After I received my replacement jar, I started making cashew butter again. This time, it took only one try to break the jar, a broken black rubber ring was found in my cashew butter. I wondered where did this thing come from? There was no noise or smoke this time. I got curious about what happened so I compared my broken twister jar with the photo of blade assembly on the Amazon product page. It turns out that there should be a black rubber ring between the blade and the base of the jar. Upon close examination the black rubber ring on my jar was gone; I figured it got into my cashew butter due to the severe friction force from blending the raw cashew. At that point I realized that the tiny black pieces found in the butter from my 1st jar were shredded pieces of the rubber ring. Look at the photo of my twister jar and you will find there's no black rubber ring between the blade and the base of the jar. The dislocated and shredded rubber can cause health hazards. By just sending out replacement jar with exactly the same issue won’t solve the problem. Blendtec should recall the product and redesign the blade assembly. Buyer beware.