Tyler wrote a review of Granite Gear Round Rock Solid Compression Sack on February 24, 2012
I haven't gotten a chance to "get out" with these sacks but since I got them a few weeks ago, I have stuffed and compressed everything imaginable. They seem very strong and well put together, you can reef of them and not worry about tearing something. All in all, I'll be buying more. I was also able to get my Mountain Hardwear Lightpath 3 (body, fly, footprint) in this thing and squish it down to nothing.
In the picture is the XL with 3 sleeping bags.. Sierra Designs Arrow Rock 30, and 2 SD Big Dog 35's. It took some effort but I think it did a great job.