Hi there.
I've been taking maca for a little while now. I know it definitely helped me to ovulate. I was having cycle tracking, so regular blood tests etc to see when I ovulated. My cycles had been irregular and some had been anovulatory. The cycle I started maca I got an immediate improvement in my estrogen and my follicles started developing properly, which hadn't been happening previously. I ovulated pretty well and had a 14 day luteal phase for the first time, but BFN.
This cycle was a bit strange, I had an HSG and I just didn't ovulate when I should have, but eventually it happened and again my hormone levels have been really good and I think it's going well so far, I'm 4dpo now.
I haven't noticed much of a change in my energy. I did read that it's best to start at a low dose and gradually work your way up with maca, so that's what I did. And I find it's better to take it after food, one time I didn't and had some stomach problems (nothing too bad).
I've never tried soy isoflavones, so I don't know if it's better or not. It might depend on exactly what your problem is. But maca is probably worth trying first, I think it's a bit safer than something like soy.