wogga wrote a review of Kelty Cosmic Sleeping Bag: 0 Degree Synthetic on March 9, 2011
I bought this right after buying a Northface 0 degree Snowshoe sythetic bag.
This one isn't quite as light or as nice as the snowshoe but it's less money and the differences weren't that huge. I'm pleased and you will be too.
One glaring omission that you'll want to correct is the omission of a compression sack. It does come wth a regular sack, but when compressed it squeezes down nice and small - same as the more expensive bag(s).
For around 4 lbs in this price range, this is pretty good - especially if you already have a compression sack you can use to get it down to 'down' bag size in your pack. Go ahead, buy it.