For the last year, I've owned only two sleeping bags, the REI Halo +40 Women's Long and the REI Halo +10 Women's Long. I've arrived at these two bags because of 1. the seasonal 20% off one full-priced item coupons they give out and the relatively low price, 2. REI's rapaciously excellent return policy, and 3. their value over the men's version.
For example, the Women's 40º Halo Long is EN rated for men down to 28º, has 12.3oz of 750 fill power down, weighs 26oz, and costs $209, while the men's version is EN rated for men to 37º, has 9.5oz of 750 fill power down, weighs 24oz, and costs $199.
With the regular 20% off coupons, you get a 1lb,10oz, 28º bag with REI's return policy for $167. Compared to a Western Mountaineering Megalite (the closest bag to compare to?), you gain 5" of shoulder room, lose 2º of range, is 2oz lighter, but—perhaps most importantly—more than twice as expensive.
Am I missing something, or is this one of the best kept secrets for the price-constrained, <= 6' backpacker?