The Nav V is very good.
The Nav VI version I has / had some problems. These were reportedly solved in version II, the so called ‘Make life a ride’ iteration. That may well be true, except I had a brand new (fresh out of its BMW box, version II which suddenly developed demonic possession. It has gone back to BMW and I await news from them. It was odd as it behaved just fine for days on end but then suddenly went haywire. It might of course be my 850 that is causing it, we shall see. I would normally have slotted in my Nav V to see if the problem manifested itself there too. But I didn’t have it with me. I simply took the new Nav VI back to BMW, Park Lane.
A Navigator VI version I that I owned, which you might have expected to go wrong, never did. I sold it on this forum with a clear conscience, simply as BMW gave me a version II as a free gift when I bought my 850.
Make what you will of that lot.
PS If you don’t value the whirlywheely thing, the XT is very good, arguably better than the Navigator V or VI. Similarly, the BMW Connected app, if you want to go down the phone / TFT screen route is pretty good, at least in my experience. That is something for me to admit, not least as I like my GPS devices. The advantage of going down the Connected app / phone route is maybe that, with the BMW conversion cradle, the whirlywheel comes back into play. But, I think, the app probably works best with the larger TFT screen. It really is just:
A. A matter of choice.
B. A matter of cost.
C. A matter as to how much and for what purpose you intend to use any navigation aid. Not least, how much creation you want to do of your own bespoke routes, as opposed to having an algorithm work them out for you. Lots of people on this site (and in life in general) are more than happy with the latter, of course. No shame in that.