Vapor barrier clothing is more effective than a vapor barrier bag. It establishes 100% humidity closer to the skin, which stops perspiration faster. The less you sweat, the less energy used in evaporative cooling, and the warmer you will be. Of course this is the entire idea behind vapor barriers, it just works better in vapor barrier clothing. One can also wear clothing over the vapor barrier liner, allowing maximum versatility. I do not sweat much so i find vapor barriers work great for me. however, comfort is largely subjective to the user.