Like I said, I own all of the original jackets listed and then some. Here are some of my thoughts:
*Sitka Kelvin Down - Awesome jacket but for me doesn't work as a puffy. I love wearing this as a casual coat though! The jacket is just too much jacket for me to consider it a "puffy" for hunting purposes unless I am using as a treestand layer jacket.
*First Lite - I've used this as an "outer puffy" on a couple hunts. Works great for that application, but is still plenty of jacket for me to be considered a true under garmet puffy. Again, awesome jacket but for me works better as an outer layer.
*Sitka Kelvin Lite - Nice jacket, nice weight compresses "ok". Though this is a nice jacket, there are better choices out there for the money.
*KUIU Spin Drift - This used to be my favorite Primoloft Puffy. Compresses nicely, works well as a inner puffy or outer layer.
*Kryptek Kratos - My new favorite synthetic puffy. Compresses well, is very light weight, fits great and just plain does it's job. Of all the puffys listed, this is my second favorite.
*KUIU Superdown - I have all three of these and they each have their own place in my "puffy arsenal". To me, these are in a class by themselves. Super light, they compress fantastic and they just plain work. They are also very warm. In fact they are too warm to hike in. Overall, I have yet to find anything I like better. Awesome product.
On late season hunts I am now carrying a KUIU Superdown as an inner puffy, the First Lite or Spin Drift as an outer puffy in addition to the Super Down pants. The stuff weighs so little and takes up so little room I see no reason to not carry all three. On a recent October sheep hunt in BC, I typically wore the Super Down with my KUIU Yukon Jacket for the 2 hours horseback ride everyday. For hiking, I'd remove the SD. While glassing on a windswept snowy mountain side, I would put the Super Down, Yukon AND First LIte Jacket on along with the Super Down pants! I was never cold in some horrible conditions.
If you only want one puffy to do it all, I would go with the KUIU Super Down. TO me the KUIU SD is in a class by itself.