Materials
The corset itself is made of a satiny, brocade like material. It doesn't feel particularly smooth or pleasant to the touch, but it does look nice and shiny. The laces are made of something resembling satin. They are sturdy and are a shiny white that matches the corset.

This corset has plastic boning, which isn't as strong as steel boning. But plastic boning is common in this price range and works well enough. Some people prefer the give that plastic boning has rather than the rigid, unforgiving feel of steel.

Looks
No one wears a corset for comfort; what's really important is how a corset makes you look, and in this department the Tres Sexy fails... utterly. Instead of producing the desired hourglass figure that one is presumably looking for in a corset, the Tres Sexy produces a sort of uncomfortable boxy shape that is not really desirable at all. It isn't just my body type, I've seen quite a few people wear it now and its never produced another look. I'm not sure if this is due to the plastic boning or the low quality material, but it certainly isn't great for a corset.
The plain white of the corset is also uninspired. I wish there were some sort of accent color or embroidery. The jewels help a bit, but they aren't secured all that well and don't actually add much to the overall look.
The ruffles at the top and bottom of this corset are the only redeeming features for its looks. They add some sort of interest to the otherwise dull texture of the corset.

Fit
The corset fits well enough, the small size fits me and I am a size 5-7 in dresses. It is obviously adjustable and will fit a wide variety of cup sizes, I'm a C and while I wasn't spilling out of the corset my breasts weren't hidden completely either.