It's been a miracle for me in helping with soreness/recovery after weight lifting.

There are three substances widely supported by research to aid in muscle building. They are whey protein, creatine (if you don’t eat much red meat) and caffeine (for the general performance boost).

Whey protein is useful if you don’t get enough protein for your needs from real foods. Note that people’s need for protein varies wildly based on activity level and goals. People doing resistance training to add muscle mass need more. If you aren’t doing that, you need much less.

The forums on MyFitnessPal.com have many evidence based threads on protein requirements.

I use it and it's fine as far as I can tell. I don't use it as a supplement but rather as a replacement.

If young and growing and very active it might be good.
If not young and body building I will not take it.

Is powdered whey protein bad for you or can it be a good supplement?