Navigation – What’s good?

Have you any experience of what is good and can’t make recommendations? I think of sense/advantage or quality of: – installation or portable – TMC or alternatives – manufacturer (quality, service) – map material (possibility of a door-to-door route e.g. from Germany to abroad and/or the other way around) – announcement quality (e.g. the announcement comes in time)? Ultimately, what is involved is to be able to use what is happening in my Saab, so I once allowed myself the question here in this forum. Greeting, A’man