The journey we did yesterday should have been almost entirely on A-roads (yes, a rarity in this part of the world). Instead, the Tesla satnav kept trying to take us off the A-road and onto unclassified roads simply because it made for a more direct (if much slower) route. (We had Google maps running on a phone at the same time and it didn't default to that route, and even if it had, the key difference is, of course, is that you can easily select an alternate route.)
It's not the first time this has happened on this holiday, which makes me think that the system is at its best in cities and with nice straight main roads, which wouldn't be a complete surprise given that it's an American car that (despite the steering wheel!) still seems to select the profile of whoever's sitting on the left of the car.