This waist compressor works!  I purchased a large and it did indeed flatten and reduce My waist.  So much so that the large is now to big and I have to go to a medium.  Overall good product.

Updated June 16, 2013

The large worked well and now no longer has a tight fit.  So I just purchased a medium.  It's a little snug but that is how it is suppose to be until your stomach shapes to fit and you lose inches off the waist. I have it hooked on the first row of snaps.