I have the perfect bag for you, I have tested the Wiggys Ultralight, Cats Meow and the Mountain Hardware UltraLamina 15. I was looking for a bag that was rated around 15-20 degrees and synthetic. So I tested all of them out. They were all really very good but I only kept one in the end. I did not go with a down bag because of cost, loft retention, if it get wet you can forget staying warm and so on. But down has a ton of huge pluses that synthetics does not. Weight and compression size are Downs biggest pluses! The same temp bags tend to be lighter smaller and compress far more then synthetic bags. But the synthetics are cheaper and wick moisture a little better. These bags are all mummy cuts. Mummy cuts arent as comfortable as rectangle but they are warmer and tend to be smaller and lighter as well. If you car camp go for comfort...if you pack weight and size are what you need. The three bags I mentioned are in your Price range as well.
Let me start with the wiggys bag first. It is easily built the best, heavy duty, big, warm and comfortable. His lamilite insulation is actually Climashield Combat so it is not his own (Northface uses climashield prism a similar holofiber synthetic insulation). It is an excellent insulation that will hold its loft better then any other bag out there. It can be compressed several hundred maybe a thousand times and still return to its 100% loft! But this is a trade off here. Because it loft bounces back so well it also doesnt compress as well and is also heavier. So of the 3 bags this is the biggest when compressed and the heaviest! And by a pretty good margin. Wiggy uses YKK #10 zipper on all his bags...these are nice and do not snag! They are the best and most reliable zipper I have used in a sleeping bag. But they are big and add to the weight. He also throws in a pillow...but it is hard and big, oh and takes up space so I just wad up my jacket and sleep on it as a pillow, the wiggys pillow never makes it out. His bags have a lifetime warranty and they will probably out last you or anyone you were to pass it on to. His outer shell is also thicker and tougher. It is a great bag the most durable of the bunch and more or less will keep you warmer over many years of use because it will maintain its loft far better!!! If the SHTF happens his bag is the one I want! This bag was easy to get in and out off as well.
The Northface Cats Meow is an awesome bag and would probably be my favorite with the exception of one thing...it is too narrow and tight in the inside. It too bad because it is really a great bag but being too tight is a huge drawback for me and I am not a heavy nor big guy for that matter. But there are a ton of things to like for I like the glow in the dark zippers and the location of them as well. It is the cheapest bag of the bunch and will last a long time as well. Northface has been making this bag with minor changes for over 20 years...because it works. But for me too tight. I am 5' 9" and 170lbs it was a too confining for in the legs and shoulders. the bag seemed to be very warm and could fend well, I dont believe it would go down to its rated temp of 20 but I usually dont think that of a down bag as well because of how light they are and they manage. It might just do it...I didnt have that low of a temp to test at. The overall design of this bag is excellent. If they made it in a wide...I am in! It even looks nice! Zippers are decent and the bag was easy to get in and out of.
The Mountain Hardware UltraLamina 15 degree is what I ended up keeping of the three. For a ton of reasons, the insulation is similar in weight and size to down because of that it compress down extremely well! It is also significantly lighter then the Wiggys but not as light as the Cats, they were supper close in weight. It did compress substantially better than the others. it was wider in the inside then the cats and very close to the wiggys (I got the wide size in the wiggys). It isn't as tough as the wiggys but close to the cats. The part that sold me on this bag was its compression size...it is small for a syn. therefore packs well. However once again, if the cats was wider...I would have kept it for I like the zippers better and the overall design it was just far to tight for my liking. Some are fine with that just not me...I tend to move around alot when I sleep and even the wiggy and the Mountain still felt a little tight at time but the cats...i couldnt take it. I didnt like getting in and out of the ultralamina as much as the other but it wasnt terrible. Once again what sold me was compression size and width...this bag was pretty comfortable for the most part and the insulation wicked well for a 15 degree bag. It is an excellent bag and offers size like down performance, weight like down, and just ended up fitting the bill the best...it also felt warm without getting too hot!
One extreme important thing to remember is your bag is only as good as your sleeping pad. If you are sleeping on the ground and it is going to be cold...I dont care what bag you have, you will get cold! So if your conditions are going to put you on cool or cold ground...get a sleeping pad that is 1.5" thick or better...without one you will have a cold and horrible night sleep! Not only do they shield you from the cold ground but they make sleeping a ton more comfortable! I like the Therm-a-rest prolite plus. it is light, small, tough and extremely comfortable. Dont skimp on the pad..it is so important in cool and cold situation it is unbelievable the difference
