Thread: Lightweight sleeping bags (Mont Bell?)

Righto, following up from the tent thread.
My Mountain Hardware bag is sweet. A 650 down bag with lots of fill but bulky, it seldom comes out due to this and I will normally use a reasonably new Macpac Latitude 500 unless it is very cold. Again a great bag but again bulky. I originally bought a Sanctuary with 800 down but I had large reservations as to its ability to keep me warm when I could see straight through it even when left to loft for some time! It was too off putting to trial on the hill.
I missed out on a cheap Mont Bell Super Spiral UL #3 the other night and am kicking myself and am thinking this will be the bag for me.
The newer 800 series Mont Bell is around 600g and I think will be what I'm after. Any other suggestions?
Anyone rate the Mont Bell bags?