Idk, pedestrian navigation has been pretty decent for me so far. (There’s been one case of it showing a path in Tbilisi that would require me to jump from a 3 m wall, but it was exactly once.) I suppose it depends on which city you’re in and how well mapped it is on the OSM.

Where it’s lacking is POIs – there’s way more stuff on Google Maps, and if I’m looking for some place in particular, I usually go straight to Google, then copy the location over to CoMaps.¹ I then try to add it to OSM when I have the time. Still again, there’s no reviews or photos (in the app; OSM does support photo linking).

Public transit is another problem. It’s usually okay for metro (MRT/LRT/etc), but I wouldn’t trust it with buses just yet.

¹ – yes, there’s been another fork: https://en.wikipedia.org/wiki/CoMaps#History

I used OrganicMaps for navigation from the UK through France, Germany, Switzerland, back into France and then Spain last year on a 2 week enjoyable camper van trip. It can take a while for routing changes if you ignore it and decide to drive elsewhere, and I don't really use the voice alerts (I just have it on my phone on the dashboard via a magnet), but all in all it worked really well.

Although I would like speed limits shown in MPH in the UK, OrganicMaps' KMH limits were useful on the Continent.

FWIW Organic Maps are aware of this issue. In the poll on their mastodon account, lack of public transit information was voted as number one missing feature. As far as I’m aware, they are looking into integrating the public APIs for it wherever possible.

Öffi, if it has coverage for the areas relevant to you: https://oeffi.schildbach.de/index.html