I have the Core underwear; the Traverse underwear; the Ascent pants; the 90% pants and jacket; the Celcius bibs, vest and jacket; the Kelvin vest and jacket; the Traverse beanie; the Sitka cap; the Jetstream hat; the Ascent 14, Flash 32 and Bivy 45 packs; and some duplicates (and triplicates) in the underwear, bibs, pants and jackets. I have no idea how much money I have spent on Sitka Gear, but it is a lot, and I have no regrets. I also have a lot of Cabela's hunting clothing, Smart Wool, ASAT clothing, Predator clothing, etc., that are all nice; however, the Sitka Gear is the best all around hunting clothing I have found.
I did continue to get cold on stand, even with the Celcius bibs, vest and jacket over all the underwear layers, until I got the Kelvin vest and jacket! The vest adds enough insulation to keep me comfortable in many situations, but the jacket is more versatile in my experience and adds about 10 degrees more than the vest to the bottom of my comfort range. I also like to use well insulated boots, additional head and neck insulation, and a handwarmer muff with chemical heat packs when the temperatures dip low and the winds blow hard. Sitka Gear is very versatile and is light and compact compared to other clothing I have. It stretches and is slim fitting, which is nice for climbing in and out of trees and shooting my bow. The real secret to making Sitka Gear work in the widest variety of conditions is to add the Kelvin vest and/or jacket to complete the set.
I have worn my Sitka Gear from south Texas to the northern Yukon Territory and have stayed comfortable in every climate and temperature range. If I were hunting polar bear or muskox on the frozen ice fields of the north during winter, I would wear very specialized cold weather clothing, because the Sitka Gear would not be warm enough. And if I were in the steaming jungles of Africa or South America, I would wear lighter clothing adapted specifically to that climate. For just about everything else, the Sitka Gear I have works extremely well. The Core top and Ascent pants breath very well in hotter weather. Changing over to the 90% clothing works well as the temperatures cool. Adding the Traverse underwear and then switching to the Celcius outerwear lets me stay comfortable until the weather gets really cold and I have to put on my Kelvin vest or jacket. When I want to have the least amount of clothing for the widest range of temperatures, like when I am in the Yukon, I take my Core and Traverse underwear, 90% pants and jacket, and Kelvin jacket, along with other accessories like a beanie, hat, gloves, etc. A light set of rain gear is also advisable, but buy something less expensive than the Sitka Gear rain suit, because it is outrageously expensive for what you are getting. I choose Cabela's rain gear. With the more limited set of Sitka Gear I just described, I sometimes am a little hot and other times can be a little cold, but it works well unless I am inactive, like sitting in a stand on a cold day.
No, I am not sponsored by Sitka Gear, but I wish I were for what everything has ended up costing me! I went hunting in New Mexico recently and every client in camp was outfitted in Sitka Gear. All of them (including me) loved their clothing and were glad they had bought it despite its high cost.
Allan