I have never tried this brand before so was taking a chance (b/c I like the cut of this top) and based my purchase mainly on the other reviews. I purchased 3 different styles, 2 in mediums, 1 in a small b/c I just didn't know how they ran.  I'm 5'2", 115-120lbs, B cup.  I got the (S) in the Sangria/Storm and it is just absolutely GORgeous!  I will definitely buy this brand again. I was pleasantly surprised when I opened the package at how it is sooo much nicer than what the pic is able to depict. The small does fit me and I'm anxious to get the (M) sizes to compare.  The mateial is a medium-weight fabric.  Not too heavy or thick for yoga/hot yoga but not too flimsy for the gym or an exercise class. I would recommend wearing a sports bra underneath for a higher impact class but for yoga, pilates this top is just perfect!  I do disagree w/the review that it is too low-cut for any 'real' exercise.  I suppose a turtleneck would be the solution for that b/c I consider myself a modest person and don't like to be exposed.  I feel 110% comfortable in this top!!