I bought these for part of a Halloween costume but I think will be able to wear them out for a night on the town to bars or clubs - but they're certainly not for a nice evening out.  Here are some more fit and material details for people who are having a hard time deciding on size:

I'm a fit 5'7 and 122lbs, normally wear a size 4 (26/27) and purchased a size small.  It fit perfectly, the elastic waistband is not very tight and did not create a muffin top, and the pants were a perfect length.  I have a pretty flat butt, and these pants have a very low rise in the back and I had to keep pulling them up so that my butt crack didn't show.  I don't know if this problem would be solved with going a size up, but I don't know if the pants would have fit as well if I had gone a size up.  The lacing up the back is very tight and needs to be untied and loosened before wearing to have them appear somewhat as they do in the photo, but never quite look the same - maybe if you have thicker legs you can stretch the legs out more and the laces will look more open.  The material is a little see-through, but it's not terribly obvious.  You'll need to wear solid color underwear, preferably a thong, in black or nude.

As for the make, the tag says the pants are 92% polyester and 8% spandex.  Hand wash warm, non-chlorine bleach, drip dry, do not iron.  Made in China.

They're fun, figure-flattering, and worth it for the money.  I have a pair of similar looking leggings from American Apparel which I purchased for about $50 and these look just as good, though I'm sure these won't last nearly as long.  My main complaint is that you have to keep pulling them up in the back.