I am always skeptical about buying jeans or clothing online unless I know my exact size in that specific style and brand.  However for 20 dollars and jeggings at that (yea I've always wanted a pair) I thought what the heck? It's an Amazon Prime deal too so if it doesn't fit I can ship it back.  I am a size 6 in women's and a size 7 in juniors.  I ordered the medium in the dark grey, and they were just a little loose on the waist area but fit perfectly everywhere else.  The two best parts of these jeans were:

1. The length. Most leggings or stretch jeans have a short inseam and I have long legs.  These left me with a little extra fabric so that if I wanted to wear heels or they shrank it wouldn't be above my ankles.

2. I love the elastic waist band.  Usually I'd be wary of the elastic waistband (think flashbacks to grandpa's fake light blue 'jean' material pants) but I loved how flat they were without the button and zipper.  This allowed me to wear tighter and longer shirts without having the bulge in the fabric where the zipper and button usually go.

Now I've had them for about a week and wore them twice then washed them.  While they only shrank a little I noticed that there were fine pickings or snags on the jeans.  It made them look cheaper than I would have liked.  I have a little sweater shaver though and took about 15 minutes to clear out all the snags, and they looked like when I bought them.  If you're looking for cheap jeggings then these are great, if you're looking for something with more... wear ability and class, then check out BCBG's Jeggings or Jessica Simpsons both look nice and more expensive on.  These are perfect for me for wearing under UGGs and with a long shirt or sweater; I just ordered the darker wash in a different style.

EDITED: After having them for about a month and washing them three times those snags grew worse, so bad that I ended up giving them away to goodwill, I purchased Huges women's jeggings, and those seem to hold up better during the washings and are made with more stretchy material.