My favorite waterfowl hunting piece is Drake's Eqwader ¾-Zip Top. It's my staple that I plan my entire layering system around, even if I'm not wearing waders. Here's why: 90% of my waterfowl hunting is done from a heated blind. The other 10% is done in waders either in blinds or in ponds.
When standing in the blind, nothing but my arms, shoulders and head extend out of the blind (and the heat). That means nothing but my arms, shoulders and head need protecting. Since I prefer to wear a ball cap over a hood, the system suits my style of hunting just fine.
The remainder of my body is well protected inside the blind. Layering heavier would both inhibit my freedom of movement and possibly be overdoing it when the action is slow and you're standing while watching for the next flock of birds. The only real downside is walking in and out of my hunting spot. The layering might be a little light for frigid mornings, but it inspires you not to dawdle on the walk in.
Drake's Eqwader system is perfect for wearing with waders. It provides the right amount of protection both above and below the waders. The core of the whole garment is heat-retaining fleece. The soft fleece below the chest provides the right mix of breathability and warmth during both active and stationary situations. Outside the waders, from the chest up, is the same fleece base but with an added layer of waterproof, windproof microfleece for maximum protection from the elements.
Having that split level of protection really allows you to layer properly for the weather conditions. It also dramatically cuts down on wasted bulk inside waders. As an added bonus, and I've done this several times, the change in materials allows you to fold down your wader top and cool off if the day has become warmer than expected. You don't have to wrestle with untucking a coat, the breathability of the fleece takes over and vents naturally. It also dries quickly if you happen to splash water over your waters and on to the fleece.
Other Eqwader features include a zippered chest pocket for storing extra gear or shells and a magnetic call pocket that keeps your "back-up" call separated from your main call you like to use, or keeps your duck calls separate from your goose calls, for example. Lastly, neoprene cuffs have saved my arms from water several times when setting decoys. You don't know how big that feature is until you experience in the field.
To be fair, since this design broke on the market, you've seen a lot of other hybrid tops pick up and run with it. Cabela's P.I.T. series accomplishes many of the same principles as the Eqwader series but with enhanced protection down the sides of the body where wet arms might land. I'm sure they do a good job as well, I just haven't had the field experience with them that I have with my Drake.
If you're a waterfowler looking for a new garment, or you have a new waterfowler to outfit, I suggest considering the Drake system. It'll find its uses through all seasons and all types of weather.
Click this link to purchase: Drake Eqwader MST Quarter-Zip