most the people here say O'Donnell
personally I use Traxxas topfuel but that was more out of what they had in stock when I ran out than preference. Seems they ALWAYS have topfuel in stock at my LHS but always run out of O'Donnell and the other brands when I need fuel. BTW most ppl say the traxxas fuel has wayyy too much oil in it and thats why most hate it.