Don't have an S-500 but I do have a Legacy, so same guitar with different electronics. I also have an ASAT Classic semi-hollow.
These replaced two Custom-Shop Fenders, so that'll tell you what I think of their overall quality. I've owned two other Legacy's in the past as well, but I prefer this one as it has an ash body and those were both alder - the ash seems snappier, more "Stratty" in tone.
The hardware and pickups are miles better than Fender IMO. Build quality from a woodworking standpoint is easily the match of Fender Custom, at half the price, plus G&L is basically a custom shop in their own right: you can pretty much get it any way you want it. Lots of little things too, like real MOP inlays and bone nuts stock, lots of obvious hand workmanship (they still use the original jigs that Leo Fender built in the '50's to shape the bodies and necks) and it's a local (to SoCal at least) small business, so I like to support them.
Really hard to do better, even before you factor in the super-reasonable prices.
Edit: I should mention, since my ASAT has them, that the MFD pickups are
good-freaking-god awesome. They are not like traditional single coils, but still retain the sparkle and spank, while giving the pickups much bigger balls.