My experience with river boats is limited to an aluminium canoe, aluminium 1971 16ft drift boat and newer 16ft fiberglass clackacraft with dimpled flexible floor. No experience with rafts, but they look like fun on skinny water too small for a rigid boat.
I love the drift boats. both have advantages. old boat is beat up so i concentrate more on the fish than worrying about damaging the boat.
I love having room in both drift boats for all gear and comforts such as extra rain gear food and any tackle rods I want to bring.
Clacka's best feature was it's interior. I liked adjustable seats so you can level the boat out depending on passengers and load. downside to fiberglass was it was beautiful, so any banging on exposed rocks put nasty scratches in it. Also had to polish was the fiberglass to keep it purdy. the clack seemed heavier than my old, plain aluminum drift boat. It may have been because the clack had lockable storage, so more gear ended up being stored in it than was necessary. For example, lights are not needed for river runs, only on lakes but we kept them in it year round. Same thing for life jackets, we tended to keep more on the boat than were needed. Where as my old boat has no lockable storage so only items needed for daily float are loaded into it. The rest stays in the drift boat Rubbermaid containers in the garage.