I've always been one to use zip locks, but last summer decided to buy a few of the Eagle Creek packing folders and ebags packing cubes, just to try them. Some people here on the DIS had recommended them. I found I like them much better that the zip locks, especially the medium and large packing folders. I found I can put more in them, than I ever could a zip lock. Those things just keep stretching and if you use the plastic packing guide that comes with the packing folders your clothes don't wrinkle. I bought three medium square cubes and also three of the smaller long oblong cube, plus a couple of packing folders. I like them so much that when I found some on sale at TJ Maxx I bought a bunch more. They are all I pack with now. As far as the packing folders I prefer the 18" medium size over the 20" large or 15" small ones. Really I prefer the folders over the cubes, but use both. Last Sept I was able to squeeze two thin dresses, four pr shorts, and four blouses into a medium cube. I was able to put 7 pr thin panties, 7 thin cotton bras, and a thin nightgown into one of the oblong shaped cubes. When I went on a cruise in January I packed all of my day clothes for a week in an 18" packing folder. Because the cubes and folders keep their nice square shape it makes it very easy to arrange them neatly in a suitcase or carry on and because of the mesh tops you don't have to worry about sqeezing air out, there's no way air can be trapped in them. Look them both up on ebags.com and read the reviews.
Again our TJ Maxx had them much cheaper than ebags. I bought some of the Eagle Creek folders and Eagle Creek cubes at TJ Maxx for $4.00-$14.00 each. I think they'll last forever. The ebags cubes are also nice though.