I usually wear a size XS but after reading reviews decided to get the S -- good thing.  I like these because they go all the way up to the waist -- I find that works better than a lowered waist under my workout tank top.  The material is smooth and comfortable, a little thin, but adequate.  These do not have the anti chafe seams that Lululemon boasts, but they are fine for my purposes -- spinning, stretching and weight training.  (I don't do yoga).  Best of all -- these are less than half the price of Lululemon crops, and I prefer the fit of these.  Will probably buy some more of these.

Update -- after wearing these for a few months I liked them so much that I just bought two more.  Great value.