Haven't had any problems personally but my daughter has lost stuff - she is only a block from me. I had a valuable package delivered UPS that was supposed to be signed for but like other folks mentioned the driver put it on the porch and signed for it.
I was doing Amazon Fresh for a while. I ordered some food that needed refrigeration. The food was delivered 2 hours early and the driver failed to ring the doorbell to let us know the food had arrived. I haven't ordered Amazon Fresh since since.