Here is a good article I found on non lead bullets over at the Rocky Mountain Elk Foundation website.
This echoes very much what some of the astute hunters and shooters have said on this forum.
I would say - to summarize this article - that non lead bullets are here to stay and while they will not likely replace lead / copper bullets, it will be very hard to put the genie back in the bottle.
I do not say copper bullets - I say non lead - because reading this article really helped me understand more about these new bullets - and also helped me to understand just how little I really know about bullets and their overall performance...
Hope you like it...