Personally, I try to use fleece whenever possibly. It is my main insulation layer when it starts to get cold. I use both a Pat R2 and some Expedition weight bottoms.
I have a Montbell UL Down Jacket (which is for sale) from a few years ago but I never use it because when it is cold around here to use it around freezing the air is usually damp and I don't want to take the chance. And for far below freezing I have a Montbell Alpine Jacket with a Nunatak Down Balaclava.
It would be nice to get a 100g/m2 synthetic jacket for the in-between places where the fleece is not enough and the down jacket is too much. It is just that I hate spending lots of money on pieces like synthetic that I know are not made to last for the long haul. A nice lightweight waterproof down might fit this niche if I wanted to spend big money otherwise a really cheap 100/g/m2 synth would do the trick. I know people really like 60g/m2 but those are barely warmer than my R2 and for just a few ounces more I can get a lot more warmth out of a 100g/m2. The Costco Parka sounds nice but there is not one even close to me and online does not show it. I was going to buy a $50 100 g/m2 Stoic but it sold out before I could get to it.
I don't think synthetic jackets are made in the USA. Or computers for that matter. It would be nice if someone could make one that was basically 6 openable compartments (left, right, back, collar, left arm and right arm) so that you could swap the segments out after a few years. Tha jacket that is.
But if the waterproof down really does work out if will be nice for the quilts and bags. And it would provide a nice safety check on a down jacket so that you just would not have to worry about them as much.