I used them on my trip to Disney World in December, but now that was before the major rules were officially in placed. I saw a segment on the today show with an FAA representative suggesting how to pack for the new rules, and they didn't say anything about not using the pack it cubes and folders. However, they did say that you should pack underware in clear plastic bags, so to me, that was enough to make me think that it might not be a good idea to use the pack it cubes and folders.
A few of the tips I remember are to pack your clothes on the bottom of the suitcase. Pack shoes, hairdryers, books, and heavy items on top of the clothes. Do not put any film in the checked in bags. The x-ray machines are much stronger, and will most likely damage the film.
I hope this helps.
Karen