I have one. Like Aron said, they're heavy and bulky. I don't think they're all that hard to put together and use as a system, but that's just me. Most of the time, I'll just use the green Patrol bag and can take that down into the 30's by itself (used it just last weekend down to 37 and was plenty warm with just midweight long johns...but I do sleep pretty hot though). I've used the bivy and Patrol bag down to the upper 20's before. My Patrol bag weighs 2lbs 4oz, so not terrible, but not the best by any means. I think the black bag is somewhere around 4lbs and close to another 1.5lbs for the bivy.