I have purchased these thongs twice now and have found the fit and quality to be consistent with both sets.  I purchased the second set because I was starting to find holes along the seams of the first set after about 6 months of use - particularly at the seam resting over the left hip, which also contains the tag.  However, they are all still holding up nicely with regular use, including during vigorous workouts.  I am actually incredibly surprised (and impressed!) by how breathable and absorbent these are during exercise.  One thong from the new set did have a loose thread unravel along the length of the right leg opening, but you're going to see issues like that with almost any brand of underwear.  Overall, I'm pleased and will continue to purchase more as my old sets wear out.