I was very surprised at how thin and flimsy these tiles are.  I bought them to replace old acoustic tiles, but in order for them to sit properly in the ceiling grid or support the weight of the recessed lighting I had to install them in front of the old tiles, rather than removing the old tiles.  I am pleased with the look of the new tiles, and being so thin, they were easy to cut to size where necessary.  For the price point I am satisfied.