It depends on circumstances, but given general forum rules, I'd have to give Firestar the majority -- she can fly fast enough to keep broad pace with him and (with concentration) raise the ambient temperature of the area to disorienting levels, then unleash an array of focused blasts, with only one or two needed to make contact for SM to be stunned, then she goes in for the kill.
SM's wins come from being *very* fast on the move, and using his webbing in tandem defense/offense; while Fs could make herself very hot to the touch, it would only take one solid connect to lay her low.
Majority for the lady, with the gentleman getting his fair share of wins.