I have nothing to complain about, and only good things to report!
I have tried several tuners with my 5-string bass, but none are so good at detecting the B (H) string as the PolyTune 3.
The display is bright enough for me to see in daylight and darkness, and is easy to read.
There is a dip-switch that enables true-bypass or the Bonafide-Buffer (Bonafide-Buffer also exists as a separate pedal, if you're not looking for a tuner).
There is also a setting to switch the mode between guitar and bass.
I also have an electric 6-string cello, whose strings are also easily detected by the Polytune 3.
In my pedal-chain, it is the first pedal - as far as I can hear, I have noticed no degradation or change in the sound whatsoever. To me, it sits transparently, being a wonderful silent partner enabling me to produce pleasing sounds with my band :)