I'm hanging onto my Horsethief, a first year model, maybe changes since. Mine is very warm, well made, roomier than most and very affordable since imported. The pad sleeve works very well, no insulation at all on the bottom.
I cut a now extinct Mt. Washington foam pad for exact, tight fit, omitting the head and upper neck. I use a foam or bubble wrap pillow sewed into the upper end of the pad sleeve, nothing loose inside the bag that way. Makes the pad just that much smaller when rolled.
Mt. Wash equivalent is available from gossamergear.com. Careful when cutting, pad gets too small all of a sudden. I wrecked one. Bit by bit, no more than 1/4" trims when getting close to a fit.
I think this is a winning idea, but it doesn't seem to have caught on much, don't know why. Horsethief has no hood, strange since you will need head insulation below 40-45 F for sure. I could go to freezing with this bag, wear down liners to go lower if need be. Just carry insulated headwear, which is therefore dual use, not a bad thing.
Certainly not a winter bag, but warm enough for those Sierra (And San Jacinto, San Gorgonio) nights near freezing, or for freak cold storm protection, IMO. For the 3 seasons.
Best, Todd in CC.