Some condensation issues, at some temperatures, for some people, have been reported, under some conditions, using ESB's.
They are in essence part of a vapor barrier system of insulation. Once you understand the pro's and con's of VB's and your own personal tolerances to heat and cold, they can allow you to extend bottom ranges of your present insulation significantly, and in the long run can allow you to further lighten loads, toward UL and SUL.
On the flipside you can end up swimming in your own sweat, significantly degrading the ability of the rest of your cloths and insulation to keep you warm, by loading it up with condensation, from your body, if not allowed to vent properly.
The HHSS is a good introduction into the world of VB's, but it's really just a general primer IMO.
Don't waste your breath
Don't waste your heart
Don't blister your heels
Running in the dark