I just finished a week in the San Juan mountains (Colorado) with a Sea to Summit Spark III, which I believe is the male version of the Flame series. Very comfortable, VERY light, and very warm. As a fairly restless side sleeper, my approach is to accept the fact that a roomy sleeping bag that allows me to toss and turn is going to be colder than a closer fitting bag (more space for your body to heat up), and accept the fact that a closer fitting, warmer bag is going to be twisted around me when I wake up. My Spark has a pair of nylon loops that are perfect for tying the bag down to the sleeping mat, which seems to help keep me from sliding off the mat in the night.