I have just made a quilt for my MIL from both the EQ fabric sheets and the Premium brand, the one from here in Australia, neither of them are all that stiff but the fabric is very tightly woven so I wouldn't like to try and quilt it. I have just taken it to a LAQ and she has suggested quilting around each of the photos, I will post a picture when I get it back.
Out of the 2 products I would probably prefer the Premium brand fabric sheets as they are slightly softer and more white than the EQ. But I am happy with both so far.