Anecdotally: I use Apple Maps when I need directions (mostly because it’s native/integrated and not google), for drives over an hour my experience is that the ETA time is +/- 5min even when there is lots of traffic.

Except in one edge case where my girlfriend and I were doing a 7 hour drive traveling east late at night on an empty highway and our eta increased by an hour then a little while later another hour, we were so confused and thought we might be driving in the wrong direction! Until we figured out we had crossed a time zone and it was also day light savings!

(I live in the Bay Area) It’s been mostly fine for me

It works fine, and I live in a city with some of the worst traffic in the US.

my colloquial evidence … apple maps is the most accurate in predicting time to destination and handles network instability in a way i prefer (keeps you on the track and just notifies you’re in offline mode)

google maps suggests more alternative routes that may save me time but their predictions are generally less accurate. network instability seems to cause the application to “panic” and it just starts spinning around - especially when walking through downtown areas

while google has a sleeker presentation of traffic and shows the “red highlighter of misery and frustration” on my map more precisely, it’s timing is generally wildly incorrect and apple has already routed me around the problem and with more accurate time to destination estimates

Apple gives better verbal instructions, e.g. "go past this light, then at the next, turn right" and it neatly shows which lane to be in. I can get where I am going even without looking at the map. Last time I used Google Maps it would give you no clues until it was basically "MAKE A HARD RIGHT NOW".