I have a custom strat with a schaller FR and no locking nut, just spertzels. It is probably the best guitar have, particularly great tuning stability. As good if not better than the Edge/locking nut combo I am used to.
back to topic.
I have played a few jems and rgs over the years. While the 5xx rg are usually great, the jems do have something special. More solid imho, everything just feels tighter, better fitting. Maybe that's just a guitar envy thing, as I don't own one and would dearly love to.
Saying that I did play a new FP a year or so ago that was not setup v. well. It did not impress me. I still liked the quality, but if I hadn't tried a few jems before, and knew how good they could be, then I would have been put off. You should definately try one that has had a pro setup.