flyer, as SAS says it depends on the reliability of the systems. On the 225 we have a 4-channel autopilot, a 3 channel AHRS, 3 channel air data system, and each control axis has 2 actuators (one electric, one hydraulic). So with any single failure, nothing adverse happens. Even with some double failures nothing much happens.
There comes a point when the danger of routine manual flying in bad weather exceeds the training benefit for being able to cope when the automation goes wrong.
The important thing to remember is that if it does start to malfunction, you go-around, discontinue the tricky flying bit etc and head for home
If you look at the fixed-wing world, who are 20 years ahead of us on this, many airlines prohibit manual flight below 10,000'
We will agree with them fairly soon, once the attitude adjustment has kicked in!
HC