If you're in a city or suburb with a Google office, it's spotless, including transit options that are often customized to the city itself.

If you're in a city or suburb without a Google office, it's reliable on roads but probably doesn't cover transit particularly well. I'm not sure if the Google vs. non-Google office is just a bias towards the kind of cities Google would put an office in as opposed to the presence of an office making a difference, but Pittsburgh is much better than Columbus or Jacksonville despite being a smaller city.

If you're in a rural area, it's much rougher. Private roads marked as public roads are the biggest thing I've noticed (presumably because aerial maps can't help much there), but also things like ATV tracks and driveways marked as roads and missing one-way indicators (i.e. routing the wrong way up a one-way street).

There's an attribution saying the data is coming from the local metro provider, who has their own interface for accessing the same data, but having it in google maps is nice as it integrates well with other navigation.

So I would say it comes down more to who has partnered with google to make the data more accessible.

Maybe more anecdotal, but I have had great mileage with google maps for navigation while driving too. The government department for land information does make almost all GIS data publicly available which probably helps too.

That’s awesome! What country is this, if you don’t mind me asking? GIS datasets are really fun to play with.

* Bicycle route. They're just terrible at it. Better now than they were some years ago (when major bike routes were completely ignored), but still not great. They still prefer to send you along car routes instead of dedicated bike routes, even when those are shorter.

* Construction work (I don't think TomTom will be any better at this, though). Sometimes they do know construction work is ongoing; for example the Piet Hein tunnel near my house is closed for more than a year, and Google is aware of this. But they also don't show routes across the Amsterdamse Brug, which is still open, and the only real alternative. So instead they send you across crazy detours all over the city. But recently I was riding to Diemen along the Amsterdam-Rijnkanaal, and it turned out that dike was closed due to construction work. Big work with signs everywhere, but Google had no idea, and because there wasn't an easy way around, I had to take a big detour that would have been a lot smaller if Google had been aware of this.

I use it daily to make sure my commute doesn't have any wrecks I'll have to work around, and any time I'm going somewhere unfamiliar. It really got stress tested on our way back from Tenessee during the eclipse exodus a few years ago, routed us (and lots of cars around us lol) through all sorts of Appalachia back-roads when the main highways were clogged and got us home just fine.

With the incredibly large sample size of two I have to conclude it's region specific.