If you are interested in how sleeping bags are made and want some information on down, there’s some informative short videos on the Valandre web site. I found the down processing video, particularly interesting. Valandre have a very high reputation for quality and these videos show why it is deserved. There’s a lot more to making a sleeping bag than getting some lightweight material, sewing it into tubes and then stuffing it with down.
I don’t have one of their bags (I wish I did!), so I can’t give you a view on them. I think the Bloody Mary bag looks especially innovative with two removable draught collars.