How they compare
If you're choosing between these, it comes down to budget against voice quality.
Camsoda AI is the budget pick: text chat is unlimited and free with any of its 200+ characters, and premium, with voice, photos and custom characters, costs $9.99 a month or $4.99 a month on the yearly plan.
Kupid AI's voice messages are the most human-sounding we've heard, and its characters come with detailed backstories in realistic or anime styles. The free tier is only 15 messages, though, and it's one of the pricier companion apps: the Ultra plan is $299 for 12 months, with weekly and lifetime plans too. One upside is that its plans are single payments that don't auto-renew.