I've got a Slick bag, 0 degree.

It is light and warm, but being a mummy bag it isn't too comfortable nor roomy and the material while water proof, gets "sticky" on your arms or other skin that touches it when wet. It is difficult to explain but it drives me nuts. If there's condensation and such inside the tent from wet boots/wet cloths it gets to be an uncomfortable time.
Other than that, it is a very high quality and well thought out bag.