Well seeing how Amaterasu burns even flames I think the answer is obvious, but it seems common sense has no place in this thread so I guess I'll leave it at that.
well to be honest amaterasu burns pretty slow but still because you can cast it directly in the target and does not stop before burning it's target is incomparable to normal fire
I swear Im beginning to hate Hiruzen and his fans so much. Hiruzens fans are much worse than Sasuke's and Naruto's, they're on par with Itachi fanboys.
Well Ladies and Gentlemen since everyone has it's own opinion and you can't change opinions even with facts I'll just be a fanboy and say amaterasu flames are better: (IMO)
it is shown in the fight between Itachi and Sasuke amaterasu flames win.