As long as you're not talking about CREEKING, I feel strongly that a playboat is a better option - and not just on easier runs.
I think playboats are great for big water class 4. They track well, you can turn on a dime and you can sub under big waves and holes that would surf a creeker.
I ran the Grand Canyon at 14,000 in a playboat this spring and it was great. Numbers at 3,200, S.F. Payette at 7,000 -- the playboat is the right call. Not to mention that you get to play and surf as well as just run the river.