The short answer: whichever one interprets live, inside the call itself, without routing through a hold queue or a conferenced-in third party. That's the main thing that separates AI interpretation from traditional OPI, and it's the first thing worth checking before comparing anything else — a tool that adds its own delay or requires switching dialers defeats the point.
Translatigo is built around that constraint: it runs as a Chrome extension inside whatever web-based dialer or softphone a team already uses — Avaya, Five9, Genesys, RingCentral, and similar platforms — so there's no separate integration to stand up. It's priced at $0.07 per minute, with a 20-minute free trial to hear it on an actual call before deciding. There aren't yet any officially certified dialer integrations, so it's worth a quick test against the specific platform in use.