No, XP is better and maybe the best on the market today. Combat is just available at a lower per sq yard weight. Combat is made at a production spec of 2.0 ounces per sq yard. Delta "today" is made at a production spec of 2.6 oz per sq yard. The Clo for Combat is also lower than XP by 8 to 10% but higher than Delta by a some (?).
What does that mean to me, well, I should be able to make a light weight item for a temp range of 50 degrees or so (?) out of the Combat or my Delta. Then layer it with a heavier weigh item made of XP to take me down below 40 degrees maybe as low as 35 degrees. The low temp for all this is still speculation on my part at this time. It might even be lower.
My old Delta was suppose to be 1.9 oz per sq yard but what I used for my Quilt was 2.21 oz per sq yard. I am still planning on using a lot of Delta. I will be testing my stuff with Delta, Combat and XP over the winter and through the spring rains.
I am following "Ryan's" Cocoon Line ideas for layering the items as you get lower in temperature. I just want to make my own stuff and use the best material that is easy to get. I am trying to look at all this gear as one big system. It all works together as it gets colder outside or in a lot of rain. I am trying to design the gear for my size and hope to get the lowest weigh gear possible. I have the advantage that it only has to satisfy ME.