Which is pretty good considering Ventress mastered the ability to hide using the Force, as indicated in The Cestus Deception.
I think Ventress has far more feats and kills to her name, but I favor Barriss out of unholybiasconsideration for her ability to use her surroundings to her benefit. Obi did the same thing and beat the technically superior Ventress in earlier works.
She's hardly a pushover in TCW. She has had the upper hand against Anakin twice, stalemated Obi-Wan, took on them both twice without consequence, and defeated Grievous.
She was casually toyed with by an Obi-Wan who wasn't even holding a lightsaber, and couldn't beat Ashouka.
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"The Daemon lied with every breath. It could not help itself but to deceive and dismay, to riddle and ruin. The more we conversed, the closer I drew to one singularly ineluctable fact: I would gain no wisdom here."
Yeah, from what I've seen, Ventress is not a threat. When she first came out, she was a huge threat, to just about every Jedi who wasn't named 'Mace' or 'Yoda'. Dark Rendezvous has her butchering Jedi Masters and 'The Cestus Deception' talks about her dancing around raindrops in a storm on good days. This is well before she dominates Kit Fisto and Obi-Wan barely wins.