In my book, they are just different tools.
My experience....
Maneuvering: If you have a situation where the truck needs to follow the trailer (in reverse), be lined up straight, or weave in and out of obstacles, a GN takes a lot more room to maneuver the tow vehicle, especially if you are running a truck with a long wheelbase (crew cab long bed). However, if you have situations like a tight loading area and a long trailer, being able to jack-knife the GN into place is a life-saver. Turning around in tight spaces is a win for the GN as well. Again, being able to get the trailer past 90* is a huge saver. A big part if maneuvering is axle location on the trailer. If you have axles in the back (think 18-wheeler) you have to swing the whole system. If you have axles in the middle of the trailer (think camper) than it will pivot more than swing.
Versatility: We currently only have one vehicle that can tow the GN trailer, and of course, its a crew-cab long bed. Its a long truck and a long trailer, so I am generally cautious about taking it to new places. I can push it around empty with the FEL, but if its loaded, forget about it. With the bumper pull trailers, I have options. I can use any of the trucks including the CCLB, 3/4ton suburban, the tractors; I even used the Wife's subaru to take the 16' trailer to the lumber yard for some long and light material!
Capacity: Given the same length trailer, I can put more on a GN than I can on a BP. Letting the truck take a portion of the payload is very helpful. Also, for the same length trailer, I can get more on the GN by putting payload over the hitch.
Driving: The long wheelbases of the CCLB and GN make highway driving REALLY nice. Pulling it around a city or into some small yards is a PITA.
If you can only have one, I would say get a BP unless you have a specific need for the GN. I do love out GN, but I would hate for it to be our only trailer.