Rating: 4 / 5
This is a hoodless zipless down sleeping bag with no insulation on the bottom. I decided to try this bag as a cheaper alternative to "variable-girth" sleeping bags and for the price of £110 (about $200 at the current high rate) I am very happy with it.
The bag measures 195x75cm (about 77"x30") and weighs 400-430g (~14-15oz), 200g of which are 96% fillpower 750+EU/850+US goose down. It is made in a Pertex Quantum box wall construction with insulation on the top and sides and a single layer of Pertex as bottom offering more draft resistance than the similar mesh bottom version Ryan Jordan has reviewed. If you bring a balaclava as your warm hat, the elastic neck drawcord ensures a close fit over it, also keeping drafts at bay here. Rab have chosen to put more insulation per area in the footbox than the rest of the bag, so the compartments at the head end are less stuffed - if you sleep uneasily, there is a slight tendency for the down to slide down the sides of the 4 or 5 compartments closest to the head.
It has a comfort rating of 0C (32F) - presumably with a warm hat. Personally I find it warm enough for Scottish 3 season use in combination with a tent, 3/4 length mat, hat and a baselayer.
The provided stuffsack is strong and waterproof and would be replaced by ultralight people. Pack size is 24cm x 11cm diameter (9.5"x4.3"Ø) - people with small packs can probably get away with stuffing it slightly harder. A big cotton storage sack is provided to loft the bag in when not in use. (site at http://www.rab.uk.com if you are curious)