So far I've only seen two classes in action, that being Hexer and Slayer. Hexer's been a great sidegrade to other magic casters so far, their favorite spells is Symptom Shift. Really opens up "weird support" options, it's lovely! One thing I will say is no one is interested in Muddle and Blind. Aside from it being expensive, it looks too easy to get rid of when other spells are harder to remove, and *seem* to accomplish more. To give an idea, Fabula had a spell that provided a +2 bonus to defense against ranged attacks and nobody cared about it. While the check penalties are less situational, it's fragility as a curse made everyone disinterested, even with the use of the word "instead" you provide.
Slayer, meanwhile, is just a good martial pal so far. The player has been focusing on Bane Oils for that Witcher feeling. The ability to apply status effects while "cheating" the action economy always feels good. They also love Wildlife expert, a more specific and general use version of something like Flash of Insight for the martial hunters out there, very cool!