I've used the Reese Goosebox since fall of 2012. The only issue I have is I have to put air in the air bag every time I use it. The relieve valves on the air bags sometimes have a slow leak in them. Trailer rides just fine. Got caught on the edge of a tornado last year and it behaved better than some semi's I've driven.
Last time I talked to Lippert they talked about offering it as OEM.
According to Reese since it's an RV and built to some standard (can't remember the numbers) 5th wheel rules apply and chains are not required. Since I have spare hole in my "pin box wings" I was thinking about adding a set just to avoid any discussions with law enforcement.
My Goose Box is mounted in the bottom holes. When it as not, the ends of the "wings" on the pin box mounting brackets would get too close to my bed rails for comfort. In the bottom holes I have plenty of clearance.
2012 Sundance 3100RB w/Reese Goose Box
2004 Ford F350 6.0 L PSD, CC, DRW, long bed, B&W drop ball hitch, Firestone Ride-rite air bags.