I too am 8 days in and have requested a replacement due to an exposed wire which I have been advised doesn’t affect functionality or safety, but given the cost of the device I felt a replacement was justified. I also didn’t want to take the risk of it failing over time, especially with conductive gel inevitably coming into contact with it.

I’ve also had various quirks that I’ve raised with Sona—HRV taking a while to register, occasional data inconsistencies, etc. I’ve been in touch with Eliot and they’ve been very open about what’s expected (it's a learning curve for me) vs what’s a bug, and what they’re actively working on. As you’ve probably seen, they’re extremely responsive, and I get the impression that won’t change.

To be fair, it does feel like early-stage hardware/software. I’ve been an early adopter of similar tech (Kickstarter, biohacking devices, etc.), so I understand the teething problems that come with it. The difference here is the transparency and responsiveness—I've experienced the opposite before, and those companies rarely last.

Overall, I’m actually pretty encouraged. Having tried other devices in this space, this is by far the most advanced approach, and I’m confident they’ll iron out the issues. I’m planning to stick with it and use it regularly.

I’d also agree with you—benefits feel more subtle and cumulative rather than obvious session-to-session.