wow. sounds almost defensive. whoever would've thought heme would be controversial. I have a feeling that some folks think heme molecules only exist in animals and therefore the heme-bearing veggie burger isnt vegan compatible.
bottom line, impossible burger if you want some iron in your veggie burger; beyond foods if you want a different polynuclear, aromatic molecule that is metal free.
i suspect that the beyond foods folk have a cheaper pigment source.
ps: re the defensive comment, i was referring to the beyond meat response