Many thanks for your detailed reply, Montu!
Shock
With or without SFD, you will have to double burn creatures sometimes. Shock is often the most efficient burnspell for that. Plus kills a mana dork t1. Plus allows you to rebuy and cast Phoenix on t4. In short, it's pretty versatile...
Stormbreath Dragon
I'm not sure Black Devo runs too much removal for him. He can't be killed by BB which is a plus. Also the fact that they can't really let any of your early creatures (incl. Phoenix and SFD) alive means you have a chance they are out of removal when you drop SBD. If not, it's at least a decent reply to Gary when they are tapped out. Post board he comes out obviously.
One plus of SBD is when you get into the situation where you have to use your burn on your opp's creatures not to
fall behind on the board too much, SBD can still win you the game, the other creatures often can't.
One disadvantage I see is that SBD makes your scry decisions harder. Say you're at 4 land and see a land: you may put it on the bottom and then end up drawing SBD or put it on top and never draw SBD.
Lands
Very interesting thought re: mull at 5 vs.1, never occurred to me. Given however that SFD is often a t4 play, you really wanna curve out at 4 and that's better at (at least) 23 lands I would say
Viashiono Firstblade
Can you say a little bit how he feels g1 against the various matchups? Haven't played the card md so would be keen to hear!
Hope it's not just us alone on the thread
Would be amazing if someone from the Burn thread could chime in, as the two builds are actually not that far apart (basically Skullcrack vs. Firstblade/SBD,
Shock vs. FDS).