It really depends on how well the GM runs it. Amber is rather free so the GM has to be able to adjust and make fair calls. If I go with Warfare 20 against Warfare 26, it will be a battle that takes some time. If I go on the defensive and my opponent doesn't go on the full-offensive, it will take him some time to realize he's better and I can buy time for someone to help me out (or for me to spot a way out).
The rules DO describe how certain styles would work out in a clash if you're better, much better, worse, much worse, etc, so there's intel on how things will go in a confrontation. All you're then doing is trying to influence the relative score with tricks, if you're in need of those. If you're fighting defensive vs defensive, or offensive vs defensive, or normal vs defensive, that's all described on how it works out at the different relative power levels.
I went Advanced Trump, which involves Trump traps that try to suck people through without the need of concentrating on the Trump, once their trigger is activated. Rather than using them on the offensive (would only work on people with a lower Psyche), I used them defensively: Had some on me, activated them with a verbal command. Let me trump out of a fight without having to concentrate for several seconds. That way, no opening left for the opponent to stab me.