I have this exact sleeping bag for 3 years. It is a good quality bag with two issues. The first is that the bag is very sensitive to condensation, it easily penetrates the outer layer. This is not an issue if you treat the outer layer with a water repellent spray. The second issue is the temp rating. I can compare this to the marmot, mountain hardware and western mountaineering bags, this one is by far the least accurate. At under 50 degrees (no wind) I need long base layers. If you have a tent calculate the temp inside. under 40 I need heavy base layers or double layers, for example a patagonia capalene 3 is not enough when the temp goes down closer to 40 (even at 45 its not enough to make me warm). when it goes to 35-40 range, I need a jacket as well.
Other bags require the jacket level only when the temp is within 5 degrees of rating for me, so I feel there is somewhat of a 5 degree gap in rating here. Not a big deal, especially given the price and weight, but important to know.