I have some kelvin pieces and just bought something from the ambient line. I haven’t had the weather to try out the ambient yet. FWIW lots of folks saying the ambient stuff is more a substitute for active mid layer insulation like a grid fleece. I like grid fleece a lot - Patagonia R1, first lite and core heavy weight. Too soon for me to tell If the ambient will win me over. It’s a cool idea and I am hoping I like it more than my old kelvin active jacket. It is light weight and compressible. I wonder if it will keep its loft as a mid layer.
call me biased, but if I were looking more general insulation piece, I would go kelvin aerolite. You’re only talking about 3-4 oz of weight savings With the ambient.