Are you kayaking? Rowing? Riding along? Would you pay more for a bit of comfort?
makes excellent pfds, and their Greenjacket is, in my opinion, best on the market as far as bells, whistles, comfort, and safety (in no order). But you'll hear a lot of different opinions.
I assume you're on a private trip - talk to your TL or tripmates. They'll better know you and your needs.
For more recommendations, check out this thread
. Enjoy your trip!