I tested a size XL of an earlier version of the Cablea’s Down Jacket in my lab. It cost approximately $50 on close-out, about this time of the year but a few years back. It is the 1.1 oz nylon shelled version with a nylon hood that rolled into the collar. It weighs 24.8 oz (XL). The size XL is comparable to size L in most other jackets. The jacket length only comes to waist height. It has sewn through construction, and a maximum loft of 1.5”. There was no effective DWR on the outer fabric. Cabela’s didn’t list the fill amount. Where did you find the fill amount for this year’s model?
Since the Montbell Alpine Down Jacket is one of the jackets you are considering, I will provide the warmth relative to that jacket. The 24.8 oz Cabela’s tested 75% warmer than the 17.8 oz XL Montbell Alpine Down Jacket. My test results indicate that it is filled with a down density significantly above the minimum 650 density to achieve 1 ½” loft. I just looked at their Web site for this year’s model and it has 68 reviews with the average being 4.4/5. This would match my subjective assessment of the jacket.
Of the jackets I have tested, the best in class for warmth comparable to the Cabela’s Down Jacket, was achieved by the New Balance Fugu down jacket. Although listed as size large, it has the same approximate torso dimensions as the XL Cabela’s Down Jacket. In addition, the New Balance Fugu has extended coverage to cover the seat area and an excellent DWR for a weight of 14.4 oz. The New Balance Fugu tested the same in warmth as the Cabela’s Down Jacket but at ½ the weight of the Cabela’s.
Based on my tests, I would expect that other vendor's down jackets, with specifications similar to the older model Cabela’s, should satisfy your warmth criteria and $ criteria. The weight penalty will be approximately 2x that of a comparable warmth jacket designed for UL backpacking.
Regarding your second question, neither the Cloudveil Enclosure Hooded jacket (200g of Primaloft One) or Mammut Stratus Hooded jacket (240g synthetic fill) will compete in warmth with a good down jacket. Primaloft One is close to the best possible synthetic insulation available. My lab tests have shown that, after quilting in a garment, Primaloft One as well as most of the other synthetic insulations achieve, on average, approximately ½ of the insulation vendor’s specified clo value. The vendors spec for 200g Primaloft One is 5.04 clo. Most garments, built with that insulation, will average approximately 2.5 clo. By contrast, the Cabela’s down jacket, I tested, had more than double this insulation value.