Yes, on the whole, golden shepherds are fairly easy to train. When you think of golden retrievers and German Shepherds individually, they are both very responsive to training.
They are attentive and learn quickly. They are breeds capable of following commands and quickly show respect.
As a result of this, when you combine both of these breeds together, the dog will be easy to train. While all dogs can be stubborn or mischievous, keeping on top of the training will help to prevent this.
It is important to remember that all dogs are trainable. How trained your dog is will depend on you as an owner ultimately. If you are willing to put all the time and effort required into training, then you will see the results.
However, if you do not put the time into training a Golden Shepherd, given that they are quite energetic and intelligent, you may find that the dog will not behave and will become destructive. On the whole they are fairly easy to train, and they will respond well to this.