When the lens is one of the best lenses I know. But it is by no means cheap. Processing is indeed plastic, and the autofocus is quite noisy, but it makes sharp images. For the price you can make it very appealing portrait photographs and also in low light, the result is still very overwhelming.
Anyone who wants to make beautiful portraits and investigated for a very good lens, making sharp images which here is still inexpensive, perfectly served with this lens.