A lot of people seem to dislike their brushes, especially the foundation and eyeshadow ones because they don't 'grab' pigment well enough (they're synthetic).
I personally love the blush brush - it gives a perfect, perfect application each time round and feels so soft. No shedding at all for mine, and i've had it a year. No streaking or patchiness at all, the blush lasts the whole day without a base, it's great, and i even use it to dust all over face powders/finishing powders sometimes.
I've also heard good things about the face and body brush - it's a huge powder brush, that feels really soft, but i don't own it and can't compare :]
HTH!