I currently have a Marmot Sawtooth 15 degree bag that I pair with a BA Insulated Air Core. Both have served me well enough, but I'm looking to go a little warmer, and hopefully a little lighter. I'm a very cold sleeper, and this setup, with baselayers and fleece top, is ony good to down to about 35 degrees for me. I'd like to get another 10 degrees of warmth from my system. I'd probably grab the GoLite if it were in stock. Alternatively, I'm leaning toward the Versalight.
ETA: OK, the formatting keeps messing up my table. The metrics are as follows:
rating * EN Comnfort * weight * fill * fill wt. * theoretical fill volume.
Marmot Sawtooth +15 * 15 * 26-30 * 3lbs 6oz. * 600 * 23 * 13,800
Marmot Plasma +15 Long * 15 * 29 * 1lb 15 oz * 875 * 18 * 15,750
MontBell Down Hugger #1 * n/a * 23 * 2lbs 4oz. * 800 * 20 * 16,000
Marmot Helium +15 * 15 * 28 * 2lbs 3 oz * 850 * 19.5 * 16,575
WM Versalight * 10 * n/a * 2lbs 0 oz.* 850 * 20 * 17,000
GoLite Z10 3-Season * 10 * n/a * 2lbs 3 oz * 850 * 21.5 * 18,275
WM Antelope MF reg * 5 * n/a * 2lbs 7 oz * 850 * 26 * 22,100
Any feedback will be appreciated.

