The thunderfire’s splash comes out at a faster fire rate than VC, and its already pretty accurate, so it doesn’t need VC to work. To get the Vibrapulse or Rosie to work, you need VC to tame the recoil so you can actually hit stuff, and VC fires slower than the thunderfire, meaning its less likely to cause a cryo effect (though the vibra,rosie would be more likely to, so I guess its a trade off).
I’d give the edge to the one that can operate independent of VC. Besides, with the Thunderfire being a blaster and the Vibra/Rosie being beams, they serve different enough purposes that you can just equip both.