Android phones seem to have issues with Bluetooth LE connections especially when other non-LE Bluetooth devices are connected to it. Listening to music on my Bluetooth headphones was impossible when my Pebble Time Round was paired with my old Galaxy S7 Edge or my Galaxy S6 Edge. Audio quality would degrade significantly.

Disabling LE on my Pebble worked (sort of) at the obvious expense of higher battery consumption.

This doesn't seem to be the case on the iPhones I've had, though my Pebble is much less useful on iOS than it is on Android.

Every smartwatch at the moment has compromises.