I've used all three. It's a crap shoot. Pack it really, really well, including wrapping the headstock in bubble wrap inside the case. Air-filled plastic bags are better than plastic peanuts around the case, as the peanuts shift around and settle. Even better are the molded rigid foam pieces that Gibson packs around its cases (not necessarily cases with guitars in them. The boxes and packing they use to ship cases alone are worth saving.) These are molded to fit tightly around the top of the case and the bottom, while holding the case rigidly in position the middle of the box.
I always save these, but now I've got an attic and garage full of them. My wife thinks I'm just a hoarder. She may be right.
I keep mine, also. I shipped the guitar back to bozeman exactly as they shipped it out. I won't use USPS due to poor tracking data mostly.