First, I am in more general agreement that I prefer to be able to use my "plot manipulation" resources, such as Fate Points or whatever, to bring a sub-par roll up to at least a minimal success, rather than be forced to make a "dramatic" decision to spend points beforehand and possibly only roll a 1 which doesn't help me.
However, probably the best read on this question, is that it matters just how much is "on the line", for the real answer. If it's an over the top game where it's expected that lots of action or big gestures (physical or metaphorical) are made and it is generally easy or fairly routine for players to earn back the resources they spend, so they can do it again, then the pay-first mechanic is doable, especially if it's unlikely that even a bad failure is going to just outright kill someone or permanently remove an important option. But in more adversarial gaming (not my cup of tea), players do have enough that they are mentally working on and laudably keeping straight in their heads, to see things work out, that making even a game's possible "equalizer" resources merely a roulette spin, rather than a significant way to insure at least some part of their efforts pays off solidly, could seem honestly just spiteful. I guess it could work if you were going for an extremely gritty, nihilistic atmosphere with brief glimpses of hope.
To me, I still tend to fall into the camp that views gaming as a relative analog of novels or movies, not video games. If my players take the time to read and play by the rules, make characters, invest time and thought and flesh out an avatar and entertain me and the other players, then that makes them the MAIN characters, that will be challenged and have bad things befall them from time to time, and they'll be punished for stupid moves, but mere random chance won't decimate their heroic goals, anymore than a main character in a novel or movie will fail his roll randomly and fall off a ledge he's crossing, without that being intended to be a major plot or turning point. Similarly, main characters that have these Plot Point resources should be able to use this above-normal power, unavailable to most NPCs, to affect real change.
