I bought this as a trial for this type of product.  I was not sure that it would actually be as helpful as it has turned out to be.  I was pleasantly surprised to find that the packing cubes provide excellent organization of things I travel with.  The three cube sizes are all nice, but for different things.  I use the small cube for socks and under pants, the medium for shirts and tees and the large for pants.  Each cube can hold enough for an extended trip if the cube is packed tightly.  Finding things in your suitcase (I just use a large nylon gym bag) is then very easy since everything is separated by type.  And finding things does not cause the suitcase to become a jumble of clothes... which is what happened before I got these cubes.

I liked the cubes enough that I purchased another set for myself, and one for my wife.  I highly recommend these if you travel and like to stay organized!