Well not to be rude or pretentious but IMO Marn's Zero sucks big time in UMVC3 from what i saw. Marn plays for flash. He has godlike combo's tricky mixups but plays the game like a 6 year old retarded kid. So i'm totally convinced soraky's Zero is better even tough he said he's using him to about 70%. And about that snapback i do agree on this. I have some horrible technology too with Zero and firebrand. With 2 meters you can do some pretty decent damage of a blocked Rekkoha DHC into luminous body than Firebrand unblockable set up which is garanteed. Here's what i do.
Basic Zero Bnb meterless from midscreen with Zero on my team does around 670k i simply replace rekkoha with Sentsuizan xx Buster, Raikousen, Ryuenjin then i do Rekkoha while opponent is still in the air . Opponent will have recovered thus blocking the Rekkoha in the air. But as soon as i use rekkoha i DHC into luminous body and charge up garanteed unblockable for a 450 to 500k combo meterless. Verdict basic bnb about 1,100 000 with 2 meters which is pretty good and easy. :D