I can't tell you about wearing comfort etc. since I'm a man but I can tell you that it's just good marketing (or even excellent marketing!!), they produce as cheap as possible (o.k. every company that big does :P) while spending millions on shows and ads where they don't even show their "normal" products ;).
But I would say they do have great products after all. I think that you shouldn't go after a certain brand when buying underwear, some products of a brand might be perfect while others are absolutely not comfortable. But that's why they produce in such a great variety :)