I have not used the packing cubes yet, but will be in a few weeks.  In checking them out when they were received, thee quality of the construction, the double zippers, everything about them is very impressive and I am anxious to pack to check them out.  My last trip, my clothes were thrown all,over the place and full of wrinkles, as the elastic straps in my luggage did not hold everything in place.  I hope that was the last time for that.