Paper about virgin vs. recycled lead in batteries?

Hmmmm...

If value-for-the-dollar is still with flooded cells, and given this evident problem with lead purity, what's the advantage of buying AGM's?

(Other than positioning- I understand that they can be oriented in other-than-straight-up ways)

I once thought that they were somehow immune from outgassing and could be used inside without sealing/venting, but a catastrophic failure thread on another site has recently educated me to the contrary!