The first order, I followed their measurements...  What arrived in the mail was WAY too small to wear.  I bumped it up a size figuring that surely the next size would work.  Barely.  It's still tight enough to be a bit uncomfortable (maybe that's the idea).  It did the job of slimming my midsection noticeably.  The line in the fabric is clearly visible under both tshirts and workshirts, which left me feeling self-conscious about wearing it.

Given the choice, I'd probably only consider this to be an excellent product if it was beneath a couple of layers (like a suit with jacket) or in bulky clothes (which defeats the point.)  For day to day use, I'd have to say its a no-go.