On the question of Calcium, because Calcium is used by the body to absorb Proteins, trying to get Calcium from protein rich milks is kind of pointless. The best way is dark leafy vegetables and salads.
And to add my two pennies worth to the Soy/cow debate, I am furiously against diary as anything other than a treat in a diet. We just aren't designed for it, like we aren't designed for alcohol. We may have made ourselves fairly tolerant (although many aren't especially in Asia where a lot of people are lactose intolerant) but it is not really a question of tolerance because what that really means is that dairy is affecting our digestive systems in the long run but not enough to ellicit a strong allergic reaction. The problem with this is we are damaging ourselves without knowing.
Also what other animal in nature drinks milk past weaning and moreover drinks the milk of another animal. Nature is the best guide. Just like salt isn't good for us -hello why do they say 'salt the ground'? Because plants cannot grow in salted Earth because it is BAD BAD BAD.