At our place which is run as a pretty tight ship for a number of reasons pax aren't allowed to handle the controls below 500'.
Personally I let pax fly straight and level if they want to. I tend to fly with the same group of people, some of whom are not pilots but who aren't strangers to aircraft; some have clocked up a considerable amount of time in light a/c. On a long leg it gives them something to do and it gives me a rest. And no, I don't mean I go to sleep. They can all fly a heading and altitude as well as I can, it's not rocket science.