On our boat we use floatcoats or kayaking vests exclusively - well, except for the full backup set of regular type II's accessible from the deck.
In my experience, when it gets chilly enough to want a jacket, you should be wearing flotation anyway, and nobody seems to object to the bomber-jacket style float coats.
In really warm weather a kayaking vest stays out of the way while it's on.
The problem is kids - our 1-year-old screams bloody murder when we put the PFD on him, and I haven't seen a comfortable alternative.
I was lucky with my kid. From about 4 months old he equated life vest with boat.. for some reason he likes the boat, so all happy
Float coats are an awesome idea. In the US Navy sometimes it is the only way to get a sailor to wear a PFD! They use Mustang almost exclusively. In Alaska, the norm is to skip the foul weather gear and go straight to a full one piece work suit. These however, are NOT considered PFD's until worn.. so make sure you wear them!