The mixer is not really usable as smoothie blender. In other mixers, which are made of glass, you can pour in all the ingredients, and frozen (thawed) fruits, it is not here. All ingredients must be given consecutively into it. Cake: If one wants first to whisk use foamy something before the other ingredients are added you can not just whisk the exchange with the knife. For this, the tank must go, then you can use the knife and continue working. For me, the locking of the knife did not work very well. I can not say whether this was due to me or the knife but. The MK 880 has a dough hook, but the carrier to have to be changed, you can not work with you use the whisk with the same carrier.