I just received mine here in Afghanistan; it's the 20 degree Slick bag. With their small compression bag, it does compress down much smaller than any other bag I have with that degree rating. It's almost too warm for me under the current conditions, I'm just racking out in a metal box and had to work at getting the temp low enough so I wasn't over-heating
I sleep hot anyways, so this will work for actual temps in the outdoors for me and the compression makes it perfect for smaller packs. My only complaint is that I wish the zipper went to the bottom. I did get the regular size and after considering that I don't care much for tapered foot boxes; the foot box is more "square" and quite roomy, I just prefer less tapered bags. It's fine, but I would probably have went with the the "wide" version for more comfort where temps may fluctuate. As is, I will hold my Woobie inside and really help improve the efficiency, most likely drop the temp rating another 5 to 10 degrees.
It has excellent loft. Although I haven't been on the ground outside yet, it doesn't seem to have typcial cold spots found in most bags. Overall, it's a great investment. The material is the same as the Woobie and I can attest to how tough the material is.