Anyone who tried Path of the Spell Scorned? + barb feat choice

Looking for experience with the barbarian subclass Path of the Spell Scorned from Cthulhu by Torchlight. How was it? Was it fun mechanically? Did the subclass features come into play often? Basically any opinion on the subclass.

I really like the flavor of it, and I was thinking of playing one in my next campaign. I want to lean into the subclass description of being a monster/demon hunter. It’s giving me a total Witcher-ish vibe, which I think is really cool. The campaign starts at lvl 3 and is going for lvl 20. I want to go monoclass, but I’m open for suggestions on multiclass.

I can’t decide on weapon and feat combos though. I was thinking of doing a Longsword for main weapon, so that the sap mastery could counter some of the enemies advantage from Reckless Attack. Then taking Mage Slayer at lvl 4, because it fits the flavor I’m going for. But am I leaving a lot of damage on the table for not going heavy weapon and Great Weapon Master? I’m not going for total min-maxing and all that, but I don’t want to leave a lot of potential damage either.

Or do you have any other suggestions for feats and weapons on a barbarian in general?

TL;DR: how would you build a Path of the Spell Scorned Barbarian?