I can only say that my last two walmart specials died, and died fast.
I'm running an Oster now that has two speeds; Off, and puree a concrete brick. The bottom of the unit weighs as much as a medium kettle bell and cost about as much.
For a while I have judged the quality of my electrical appliances by their weight, and it seems to work. Amplifiers, blenders, toasters, ammunition (Freudian slip), computers, cameras.... heavy = good. Very scientific, I know.
Fortunately, some savvy marketing guy in China has not recommended lead weights in their goods.
For what it is worth, I have in fact pureed a whole rat.