Yes, it can be benificial, but ...

Most soy is GMO with heavy pesticide usage, so try to stick to organic. The less processed the better, like beans, soy nuts, and tofu and miso.

I think the answer is, it depends. Soy has many positive attributes, but one of the things it does is mimic estrogen. I had estrogen sensitive breast cancer and was told to NOT eat/drink any soy products. So I don't. Although we may never know what caused my breast cancer, I feel it may have been linked years on the pill. An Aunt of mine who is a fitness fiend was eating and drinking a lot of soy products. At one point, her periods stopped altogether. Her doctor told her to quit soy products, her period resumed. A number of years later, she too got breast cancer (and is also a survivor). This is my story, but it is not the same for everybody. Many people eat soy based products and have no problems at all.

I was told that eating it in it's least processed form is best (edemame, tofu, miso.) Organic always. I use organic soy milk (not so unprocessed) as a dairy replacement because I have a food sensitivity to dairy. I have for over a year now and I don't notice anything different and my mammograms have been fine. I don't drink gobs of it though. I also think it really depends on the person. If breast cancer ran in my family's history, I'd probably avoid it to be safe, although I realize that isn't always a good indicator. Everything in moderation and I would think you'd be fine and if it makes you feel "off" stop eating it. Isn't it frustrating that we're left to wonder? I sort of look at it this way, it's more damaging to our body to eat processed foods than it is to eat whole foods, even if they have cholesterol, or estrogen, or whatever the "new" dietary faux pas is for the decade because science has proven, it can't always be trusted either. Moderation should be followed with everything.