You are absolutely right. Once you reach the tipping point and know you will spend lots of nights out of doors, pay whatever it takes to get a warm, light bag. It hurts when you cough up the dough, but the return is many nights of comfort. My first expensive bag lasted me for twenty years and even then, it was stolen; it didn't wear out. I still use its replacement, although I have supplemented it with one of those nice REI bags that indeed seem to be a good value, well balanced between weight and warmth.