At first she had some problems getting the stack reasonably straight into the slot. But after 4, 5 times she had the hang of it.
The crank sits after fitting very stable (perhaps because was rectified by the manufacturer?), But still can be removed if necessary. The whole structure seems to me quite stable and resilient.
We currently have only new, very thin cards in use. These are blended perfectly without changing the "default setting".
I would highly recommend this machine fully. However, I wonder if my child is the manual mixing ever learn if she has such a great device ;-)