I noticed the differences between the three systems:
- Waze thinks British English should sound exasperated (not sure about other languages to be fair). Gives way too many instructions. Some routes are really bad
- Mercedes has the calmest voice seems to give an acceptable amount of instructions without being in your ears all the time. Since I have ntg3.5 the routes are "standard" and maps outdated. No longer using it.
- Here gives really good routes although the voice quality isn't that good. Voice calmer than Waze. Amount of instructions can be a bit high sometimes but not as many as waze