There are 2 basic types of gyro stabilization
Rate gyros attempt to limit the rate of change of direction.
Heading hold gyros attempt to lock onto a direction.
Both are over-ridden by control inputs.
Rate is better for most fixed wing purposes as they will tend to damp out much of the effect from wind turbulence but allow the normal minor drifting associated with "straight and level" flight.
Heading hold tends to be more useful for helicopters, especially for adavnced aerobatics.
The newer 3- axis gyros can be very nice for assisting in learning to fly, if they are set up correctly. Generally this means an experienced RC pilot needs to fly the plane and make adjustments to the gyro.
An improperly set gyro can be worse than having no gyro.
You also get exactly what you pay for when getting a gyro. Cheap tends to be unreliable and/or difficult to properly adjust.