Silk long johns or Silk bag liner?

I’ve had some ThermaSilk Long Johns for about four years now and I love them. I’ve worn them in -10F to 40F and been comfortable each time, even when active. Mine have taken a beating in the washer and have holes all over the place to inclue the rear end being completely ripped out. However, I just can’t part with them for the fact that they are so comfortable.

The silk long johns make sense to me. They are more versatile. They protect your bag while providing a little more warmth and are also useable outside of the bag. I can’t think of a single advantage of a silk bag liner over silk long johns other than the weight. The versatility seems worth the weight. I however, have never used a bag liner and sleep every night in silk long johns so I may be biased.

One nice advantage of a silk liner is that in use with a quilt (or even with a sleeping bag) it drapes very nicely around you body and minimizes draft. For this reason I always use a silk liner.

I have and have used both, but most of the time take either silk baselayers or microweight wool instead of a bag liner. Like others have said, they are just more versatile- can be used to slightly boost bag ratings (or, more importantly for me, keep a bag cleaner) and can also been worn if the temperature gets colder than expected. The combination of a light baselayer, trail pants, and shell pant can be very warm for 3 season use…
Also, I find liners either too restricting, or so loose that I get tangled. I move around alot when I sleep, and either hate not being able to easily move my knees or hate getting all tangled up. I struggled with the extra weight until I saw it this way: my baselayers are part of both my clothing and sleep system, and would be carried on most trips regardless since I may need to hike in them- so it is the liner that is extra weight, not the layers. And, if extra warmth was my primary concern, 4 ounces of overfill in my down bag would do a great deal more than a bag liner.

Like Mike I too have both and have used both. I will say that I have used the LJs for more than 6 years but have only used the liner twice. The reason is that the liner is limited in utility. It is just for your bag. And it got twisted about a bit in the bag when I have used it. A pain! My Ljs are what I look forward to at the end of a day. They really feel great and provide some nice warmth in camp. Its also nice to have them on when one has to answer the call of the bladder and getting out of a warm bag is not what you want to do.