Two things make the NutriBullet Pro hard fro my wife to use. First is the force it takes to ensure a non-leaking assembly of the cup to the blade. Second is the pressure it takes to push the cup assembly onto the motor assembly. Maybe these items can be looked into. (No, I can't always be there to assemble it to make it work without hitches!).
I have had my Bullet for a month & have used it several times. It is the only way I will eat fruits so this working fine for me. I will be trying vegetable soon. I have problems getting the blades off after processing it.
I finally bit the bullet and made my first smoothie. I used kale, 1 banana, frozen strawberries and almond milk. What a great experience!!! No kale taste just fruity taste with a natural sweetness.