Although the weight difference between the Apache and Versalite is negligible, the width is not. I get very clustrophobic in the narrower bags such as the Apache or Ultralite, plus I like having the extra room to layer with the Versalite. It's not just about keeping warm while in the bag (the Versalite is a toaster), it's also about keeping a layer of warmth around me when I get up in the night or rise in the morning.
However I don't think you can go wrong with either depending on how you cope with width/lack of width issue.

