I recently replaced my 30F Polarguard Delta bag with the BA Horse Thief ("HT"). After about three years of intermittent use the synthetic bag lost much of its loft, notwithstanding being a quality bag. I decided to opt for a high loft down summer bag, thinking it would last much longer and compress smaller. I've now used the HT enough to get a feel for it. I couldn't be happier. It packs down to half the size or less of my synthetic (much easier too) and lofts right back up. (At 1 lb. 10 oz. it's also 8 oz. lighter than my synthetic.) The workmanship and materials seem to be first rate (shell, stiffening tape, fluffy collar, etc.). It's a different type bag though. It has no insulation on the bottom, so it needs to be used properly to be effective. Others have questioned the bag's temp rating; however, IMO the 35F rating is actually conservative - provided the bag is used properly. I also went for a BA Air Core 3/4 pad. At 16 oz. this pad has (IMO) the highest comfort/weight ratio available. However, I feel the pad is too thick to be used in the HT sleeve unless the temps are mild. When the pad is placed in the sleeve and inflated anywhere near its advertised 2.5" thickness it seems to compromise the temp rating by pulling some of the bag away from the body, esp. if you change positions as much as I do. The Air Core pad also doesn't insulate you much from cold ground. However, I still really like the pad and it may do double duty as a raft - LOL). I just use it under the bag, and if I think the temps may approach 40F or below I put a very thin mummy shaped "Pack-Lite" foam pad in the sleeve. This significantly improves the ground insulation but does not seem to interfere much with the "drape" of the bag. (Note that the HT sleeve is designed/shaped for a mummy pad.) BA does make an Air Core insulated with Primaloft. However, I opted for the non-insulated as it's made of 70D nylon - as opposed to the insulated version's 40D and I didn't want to worry about punctures. BTW, I purchased this bag for about half what other manufacturers charge for a comparable high loft (750 or greater) summer bag.