Also pay attention to the “comfort rating” if a company provides that. The temp rating you typically see is related to keeping you from hypothermia, not warm or comfortable. Everyone is a different type of sleeper - warm, cold, or somewhere in between. Of course you could always add layers of clothing to hit a certain rating too. I’ve stuffed bags I’ve had in the past with about every piece of clothing I had in my pack to stay warm. Buy the best quality bag you can afford. Nothing worse than losing sleep because you’re too cold (or even too hot) in the backcountry. You’ve invested a lot of time and effort in your hunt and it can be negatively impacted by something as simple as good sleep. Good luck!