When Space Bags first came out, I thought they would be terrific for storing my stash. Unfortunately, after packing a jumbo bag and vacuuming out the air as directed, it split down the side when I tried to move it, spilling the contents everywhere!
Yesterday I decided to try it again. I purchased a "combo pack" at Big Lots, which contained a jumbo, extra large, large, medium, and two travel bags for $15.
I started with the jumbo again, this time filling it with unwound hanks. I untied them and laid the twisted loop along the bottom of the bag. Although still huge (a little smaller than a baby mattress), at least this time it stayed intact. Encouraged, I filled the extra large one the same way. It's nice that they now have a "fill line" marked on the bag - I guess that little extra room at the top is required so it doesn't explode.
I found that wound skeins fit perfectly in the medium bag. I stacked 3 skeins across and about 6 skeins up - 18 skeins now the size of a standard pillow - yeah! If I had the time, I think that the large bags would do just as well and be much more uniform if filled with wound skeins.
I like the travel bag as it appears to be large enough for a full sweater project, yet small enough to fit in a tote bag. I think those will be used to keep my work in progress clean.
I believe an investment in the medium or large space bags is my next step. I was impressed by the amount of yarn I could fit in one bag, and how well the bag filled with skeins stacked in the closet. The jumbo bag, filled with hanks, is incredibly lumpy with no flat edges, but I can easily see every color that is in there.
I consider Space Bags to be a viable alternative to clear plastic bins. They are less expensive and more pliable, thus can fit in an area a bin cannot. Space Bags keep the yarn clean and fresh until you are ready to use it.