I use the inflateable pfd (manual) when I am fishing or any time the boat is not moving at speed. When running to the fishing grounds or when the boat is at speed I wear a regular pfd.
The inflatables are very comfortable to wear while fishing, working the downriggers, etc... as they allow alot of free movement. If you wish to wear one all the time get a auto inflate incase you do get knocked silly by hitting the water at speed.
I also wear my inflateable over my float coat durring the winter months blackmouth fishing, never even know its there.