Combuster. Funny how the hardest weapon to obtain in the entire game is so easily outdone by pretty common/easy to make ones.

So, let's compare.

Fang of Vog:
-Less attack. Obvious here.
-The speed meter looks the same for FoV and Combuster, right? Wrong. Fang of Vog is much slower, even though it shows the same speed.
-Less range? Haven't ever tested but FoV is really small. It shows less range than the Brandish lines.
-Charge attack is a 360, has incredible damage and can hit up to four times. This can be devastating against undead and construct. But at what cost?
--1/3 chance of being set on fire. Even with maximum fire resist.
--Even with maximum fire resist, you'll be taking 1 - 1.7 damage a tick, three ticks in total, (total 3 to 5 bars of damage) over 5 seconds of fire. This is on T3 - certainly not viable for constant use. T2 is a bit weaker, only being able to deal up to 2 bars of damage total - Somewhat usable as long as you don't spam it like a madman.
-Normal attacks have a quite high chance of fire. (20%, I think?) It's a nice additional damage, but fire is already pretty useless, so it does not matter much. It's about as powerful as a medium damage bonus would be. A bit less or more, depending on the mob race.
-Ridiculously hard to obtain.

Combuster:
-More attack power.
-Easier to obtain.
-Can have UVs.
-Attacks faster.
-More range?
-Will not set yourself on fire.
-Charge is ranged. Although it's not as generally powerful, it can be more useful since you don't have to moderate your usage of the charge.
-EXPLOSIONS

So pretty much, Fang of Vog ends up being something simply for showing off you've killed Vanaduke a lot. Combuster is the actual decent fire sword.

Fang of Vog could really do with some buffs, considering it's the hardest weapon to obtain in the game.