Duckies are fun, but I'd not recommend buying one. Their main advantage is you can throw a novice in one and run semi-difficult rapids.
If you want a single person boat, get a kayak. Much more versatile and fun.
For multiple people, a 11'-12' raft is much better than a ducky (in my opinion). A ducky can take 2 people max. A small raft you can r2 it, or bring up to 5 people if they are reasonably light. You can slap an oar rig on it and pilot it yourself or bring a passenger or two. They aren't much more than a good quality ducky, plus you've got some room for beer.
For big water, you generally want a bigger raft (14' seems to be the sweet spot) or a kayak. With a bigger raft you can do multi-day trips in comfort too.
You could also look into catarafts. They aren't as versatile, but they're much cheaper. For some reason most of the oar rigs you see on tougher sections are cats. But you can't run a cat as a paddle raft...
I don't own a raft, this is just my perspective as a kayaker who has friends who own just about every boat imaginable (five ~14' rafts, one 12' raft, one 14' cataraft, one 16' cataraft, one mini-cat, a ducky, a sit on top, and numerous kayaks).