Okay, I added the "4WAY FLEX" to the list for comparison's sake. If I'm interpreting this correctly, the Antarctica is simply two layers of the same fleece as the Flex, and the Quilted is two layers of 240g fleece plus a nylon outer shell.
Would it be reasonable to assume that the nylon outer layer isn't going to give you much additional thermal protection? If that were to be assumed, than you've for 480g of fleece in two layers for the Quilted versus 640g in two layers for the Antarctica. Hmm...
Anyone want to get one of each and spend some dives comparing them?