IMHO, those aren't made for any type of fast water. You won't see any professional river guys using them (I mean the serious whitewater guys who put more water miles then most). I know the outfitter I ran cargo for always used standard class III or III/V PFD's. If you do plan to run big water, you MUST have a standard PFD. I wouldn't even trust the auto inflates. Your life depends on it, and on the water it's only a matter of seconds you have to get that thing inflated. If you get sucked under and it hasn't inflated, you won't have enough saved breath to get her up enough to float you out. Not a risk I would want to take.
If I were you, I'd keep those for either still waters, or in situations where you have a bit more opportunity to inflate. But on a river, you hit the right hydraulic (even on small "easy" waters) you can flip. If you're knocked out, you can't pull the cord. I only use standard PFD's. If you want something with more mobility for rowing, look at the higher floatation kayak vests. It's not that hard to take them off and put on a vest if you pull off. If you're on the sticks, you won't be fishing that much, and if you do you can easily get to your other vest to grab gear.
"Good angling ethic is not a monopoly practiced just by fly fisherman" - Bill McMillan