So, there's one notable exception to the answers posted here:
The Operator's Staff, available in Chapter 3, is a viable alternative to endgame Steel Swords, and is arguably better than all of them for some Witcher builds. It offers an extremely high chance of Incineration, as well as Stun and Freeze procs, so a build with high +Critical Effects chances (possibly through carefully planned Mutagen stacking, though not needed), can reliably Incinerate or Freeze just about anyone you hit.Meanwhile, the base damage is comparable to a fully rune loaded Forgotten Vran Sword or Caerme. You sacrifice very little on that front.
However, unlike a standard Steel Sword, the Operator's Staff has an unorthodox swing animation - it has an extremely long reach and wide arc, which makes it very useful in some of the large scale brawls that characterize the end of Chapter 3, but it does take some getting used to. Finally, when carried, the Staff generates a bright light - handy for exploring some darker tunnels without a Cat potion or similar.
The downside is that since the Staff is not a Sword, but rather an 'Additional Weapon', Geralt is not his usual acrobatic self when wielding it - specifically, Quick Attacks will not have Geralt leaping to his target or bouncing around the battlefield like a ping pong ball. You'll need to be much more conscious and in control of your positioning.