This is our 3rd Nutri Bullet. We passed the 1st one on to our son when he went away to school and purchased the 900 series. Unfortunately, a piece of plastic broke off of the top which then required you to hold the unit down to get it to grind. Maybe that top ring should be metal to make it a little more durable. Also would appreciate an easy way to remove the outer casing for cleaning when someone forgets to make sure the grinding plate is on tight. This item has been a great asset to me and my morning green smoothies!