Great gadget while working out AND as off-training hours commence!
I love it, it does what its stated intent for it is. The first time you boot Vi up is magical, and absolutely amazing to hear her voice!
I strength train a lot, and only do cardio rarely now when it is so hot outside, but the times I did cardio, it was great and Vi allowed me to push further (and get occasional laughters when providing fun facts or interesting trivia).
While there has been 2-3 issues with the software (sound issues/earbud detection), it has been resolved by either reinstalling app/version, which goes quickly and has not erased any data as it is being saved on your profile.