This is pretty opinionated. But we personally find fifth wheels to be smoother rides and easier to maneuver. Having the pivot point be over your rear tires instead of the bumper means you can make much tighter turns backing up. And fifth wheel hitches can be rated for much higher loads, although if you want your max to be 30' that won't matter much to you. Finally, fifth-wheel campers typically have higher ceilings and more space for an equivalent length due to the portion that sits "up and over" the truck.
That being said, the hitches themselves are also often MUCH more expensive (all three parts of our Curt, together, were like $1700 IIRC), are very heavy, and take a lot of bed space. I think there's something to be said for both types...