How well did it work? Were you happy with it? is as good as the North face Elkhorn 0F?
J S Sorry... missed the North Face reference. Haven't used that bag before so I really can't speak to the direct comparison. My driving factors were performance (really good), price (also really good) and weight (comparable). Having always been skeptical of degree ratings I've tended to drop one rating (0 to -20).
J S Bought two of these bags for my daughters first backpacking trip into Mt. Lassen. Late spring snows raised concern not only to get into our destination but night time temps as well. (Park roads were still being plowed the week prior to our trip) Though I knew temps wouldn't get below 0, I didn't want the kids to be cold for fear they would never backpack with Dad again. I was anticipating temps in the low teens and that proved to be the case. Both slept completely comfortably.
I purchased the same bag in the Long for myself and was also completely comfortable. Don't know how much faith I had in the degree rating - probably only because of the low price paid - but figured it would be comfortable down to about 0 degrees. After a few more trips though I'm pretty confident it would handle sub 0 well. Lowest temps experienced so far has been low single digits and it performed really good.
For the price, I'd buy the bag all over again without hesitation. The only knock would be the weight (which is completely comparable to other non-down bags) but I didn't have the budget to pay "down" prices for three bags and in the end I'm not at all sorry for the purchase.