The difference was, in my experience with both metal and plastic, that the plastic blades would accelerate more than the metal ones under conditions of light or nil loading. An example is autorotation whereas metal blades with not go fast enough for a needle split unless above 6,000kgs. Plastic blades with achieve a needle split at any weight with the result that the engines back off to the idle stop which is why they take longer to react.

Another reason why the alternator trip had a delay added.

Always remember that on a zero speed EOL to apply full left pedal as the alternators trip off with the lever around your ears or the yaw/collective interlock will point you over your right shoulder.

Yes, the placcy blades suffered far less drag than the metal. However, the inertia of the RAF system meant that the old FRC advice to flare to 27 degrees nose up (!) for an OEL remained in place for far too long. We soon learned that the plastic bladers flew just like an oversized Gazelle in comparison; it was a different aircraft.

We were also led to believe that the plastic blades were far stronger than the metal ones. However, a bad batch of carbon fibre had supposedly been built into some blades and this meant that they were of unknown strength.
It was later decided that all blades on RAF aircraft needed to be ultrasonically tested. A jig was brought into the hangar, the first blade was removed from the aircraft and placed in it. The ends were supported while the middle of the blade was deflected to the specified amount, by a hydraulic jack. The idea was to listen to the blade with ultrasonic detectors; any undue noise was a sign of a bad blade.

The loud crack as the blade snapped was heard by many of us on the squadron, which rather took the edge off our confidence in them.. Sure enough, the bad blades had been sold to the RAF!