A friend of mine had a Gracey Trimmer, this guy was so machaniacally challenged I am sure he had problems with a screw driver. He brought this out to me because he tried to adjust it and it wouldn't trim anymore. I had never seen one of these trimmers before so I had him leave it with me and I told him I would look at it when I had time. ( I own a small machine shop).
Once I gave it a good look, I could see several things were out of adjustment from a machanical point of view. With a few Allen keys and 5 minutes of my time I had it back in business and trimming cases.
Gracey's are very easy to work on and adjust and are direct drive (with a coupling) while the Giruad is a belt drive. Both work fine but the Gracey has less moving parts. The benefit that the Giraud has over the Gracey is that it will lighten your pockets by an extra $105.