Obviously a First Blood match is a better way to end a feud. Do I even need to expain? I suppose I will.
First of all, an Inferno Match is an extremely niche match. Really, it only caters to feud involving Kane. That eliminates about 99% of all feuds in wrestling and 100% of feuds that are actually worth a shit.
Secondly, an Infreno match is just stupid. I know wrestling is fake and all, but do you have to make it so obvious? Setting your opponent on fire, really? I don't think anyway, not even the 7 year old Jeff Hardy fan in the front row, believes it is legit.
Thridly, Inferno matches are extremely dangerous to the wrestlers health, even more so than bleeding profusely out of their faces. From everything I've read, Inferno matches greatly restrct wrestlers ability to breath and the fire can cause some rather severe burns. It's not something I'd wish on anyone, except for maybe MVP.
Fourthly, a First Blood match is just awesome. What could be more personal or brutal than winning only by making your opponent bleed? Nothing, that's what I think. Instead of being worried about stupid pinfalls, wrestler are only worried about breaking their opponents skin, which is quite awesome.
Fifthly, the First Blood match is the signature match of none other than Ric Flair. As stated above, the Inferno match is the signature match of Kane. Obviously, Flair is better than Kane, therefore a First Blood match is better than an Inferno match. Logic 101, as a college student might say.
Sixthly and lastly, the First Blood match has been in use much longer than the Inferno match. A FB match has stood the test of time, the Inferno Match hasn't.
The end.