I don't think it is a product of the gooseneck. I have the only factory gooseneck 5er available right now. I can tell you the ride is great with the gooseneck. There is no chucking at all and the whole combo feels solid. What I do get is a transfer from the trailer to the truck when the road is very rough. It is not harsh like when the 5ers I have pull chucked in the hitch head. It is more of a knudge.
I am so sold on the goose that if I ever do go to a larger 5er it will have a goosebox on it
Chris