At 135mm it may tend to "compress" (flatten) the subject's facial features. But if you can acquire it for reasonable money, a good deal. Nice to have "fast" glass in the bag.

For head shots generally a lens of 85mm or less would be better. With 35mm film cameras a 90mm would be a personal choice for a lot of what I assume you mean by "street portraits." And still gives you a fair "stand off" distance without over-compression.