Angus Bohanon wrote an answer about Marmot Trail Wind Hooded Jacket - Men's on August 27, 2014
I'd have thought that judging them by price/ounce implied that you wanted MORE weight. The Trail Wind costs $80 (ignoring the current sale) and weighs 145g for a medium; the Tachyon costs $85 and weighs barely a third of that ? 51g for a medium. So really, if you go with the Tachyon, you're paying them $5 to cut two-thirds of the weight. Seems to me that the Tachyon wins this one.