For the price, the entire system works, and is a decent deal, BUT.. if you have the chance to pick and choose your cold weather bag, you can do a lot better.
The bivy and the patrol bag are the most useful. I've found that these two plus a a fleece insert is about the limit that I'm willing to want to sleep outside.
Look for a thermarest inflatable backpacking pad if you "need" one. They pack smaller and are more comfortable.
Everyone has their favorite extreme weather bag. The big black usgi one is huge.
The overall system packs down smaller if you keep your patrol/bivy/liner in one stuff sack, and the large bag in another. You can use smaller stuff sacks that you can really wrench down on to help save space.