What the advantages of a 5th wheel I can not tell you for I've only driven one once and it was a SEMI truck.. And many many years ago (like the 1970s) I know there must be some advantage but I do not know what it is. Will let otehrs cover that.
But there is also a "Disadvantage" in that you have that big 5th wheel gear sitting in the truck unless you remove it when not towing Takes up a whole lot of 'Floor Space' in the bed.
With a goosneck you have only the round ball and that may even retract so you have the full bed open for use when not towing and half of it when you are.
One caution however I've seen two gooseneck systems.. one is the Goose Box (I think it's by reese hitch but not sure) I have seen pictures and this is a good system to my eye.
The other is a king pin converter basically a long pipe that screws on over the king pin and has a ball hitch on the lower end.. . Now I've seen this one up close and bent all to hadies when the driver spiked the brakes (Actully it was the pin box that was bent) I would strongly recommend against it.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times