Another Dragon Vs. Balrog thing

[Firnantoonion]

my vote goes to Balrogs, simply because they are maiar spirits, in their own spiritual form, even if dragons are maiar spirits too they are less powerful because they are bound to a physical (less spiritual)form, and therefore had to use power to contain this form, wich a Balrog didn't have to.

furthermore, a dragon (take Smaug or Scatha) can be slain by mere men, no single man can handle a Balrog (save maybe hurin)
all the Balrogs (what we know of) are slain by either maiar or by powerful elflords, who all died in the process.