I use whey protein. I've read a lot about whey on some alternative health boards and the consensus there is usually whey protein as well. Of course, that's because most of them (and I don't know what to think) think that soy is not as good for you as "they" say. I imagine you have to find what works best for you but if you are using whey protein and like it then why not just stick with it if it's working for you? I've read that soy whey can fall short on taste, mixability, digestability, etc. but that it supposedly can help you to absorb other nutrients better then regular whey. So, who knows! I know this was no help and probably clear as mud but I would say do what works best for you!