I did a few more tests and after I fixed my operator errors I think it worked more or less as advertised. It certainly is not as accurate at maintaining a temperature as the Joule or the Anova.
Nonetheless I found it frustrating. It seems that every adjustment made on the iPhone must be followed by pressing the power button on the unit itself. If you don’t remember to do this then any adjustment you have made doesn’t have any effect.
My only reason for even considering one would be if I were going to make cheese in it and I don’t think it would do well maintaining temperature precisely enough.
Other than that my purpose-built sous vide units and my induction range seem less annoying to use.