After many years of good freezings, I broke down this year and bought a Western Mountaineering Highlight/Beothuk. I had been alergic to down as a kid so always avoided it since. But after doing a bit of searching info, it sounded like pure down that has been well treated and cleaned is seldom a problem for alergies.
Had it out in the Whites last week, 5 days rain, snow, 20's outside maybe low 30's inside. Bag is rated at 40F but slept fine well below that, not sneezing or itchy eyes. My wife used it one night and slept warm and she is a cold sleeper. Much warmer than the good quality 32F bag I have and less than half the weight at 15.5 oz.
Bag has a decent stuff sack that looks water resistant, but I had it in a plastic bag to be safe, stayed dry no problem over 5 days with 0 chance of anything drying even a little.
Expensive, but worth it in my view. Outer fabric seems to shed water well, like the idea of a tight weave fabric that sheds water as oposed to some sort of treatment ot coating that can break down or get washed away over time.