KMeek
I'm not much of an authority, so please take my posts for what that's worth. Mostly I'm passing information that I've heard.
The comments that I was making relate more to the overall design of a gooseneck vs 5th wheel trailer, not the coupling mechanism. If you look at the gooseneck part of a gooseneck trailer, there is usually LOTS of steel as opposed to a more simple frame on a 5th wheel camper. I agree about the bed clearance not being any different between the two hitch styles; again, I think that the comments were more related to the overall design of the trailers.
I've never used a gooseneck trailer, as my towing experience is in the RV world. Other than the 5er hitch being heavy and taking a lot of space in the truck bed, I really like the easy hookup and visability of the 5er hitch.