The WM Ultralite I used this summer was very nice. My Megalite was in getting repaired and having 2 oz of additional down added to it. I will take that to Zion NP in October where we anticipate the lows to b in the mid to low 40's. Up at Guitar Lake this summer it dropped down into the mid 30's and I was zipped up in the Ultrlite and very comfy and that's with long johns on. I am a really cold sleeper and that is why I was looking at 4 inches of loft on the quilt. I have also dropped 25lbs since the first of the year and I am thinking the Megalite might now b mega big on me. I will know in October.