Hi,
I have a 4S outer with thermaliner. Bulky, but an ace bag when you do not need to worry about space, and if things may get a little rough. I have down bags as well which are great when space is required and things are probably going to be dry.
I have used Buffalo for many years now both at work and play. I have sleeping bags that are eight years old and have been used 200 days per year min' by people who don't care. They get washed weekly, non-bio and at max only use half the soap thats recommended. Can be tumble dried or you can get in it wet and it will be dry in the morning.
The lightweight bags are good value, but you can feel restricted by their narrow cut.
4S outer with arm holes and double zippers are great if you need to move whilst resting, can be used whilst driving, you don't need to get out of the bag for a midnight pee.
What more can I say.
Paul B.