The only thing where google maps is superior is the reviews. In all other points OSM is more detailed and often more up to date. Especially due to nerds like us, that while waiting for the radicalistic-left club to open, explore a mislabeled playground, fix that, and continue to complete streets for OSM with one dude's phone that can measure distances.
However, google maps does have a lot of data too. Except the app, as all google apps, has literally no useful settings and is awful to use in many aspects.
And for FOSS apps that give traffic data: There are none that I'm aware of. There are, however, alternative, crowd sourced apps/websites for germany, like Blitzer.de, that not only show speed cams but also traffic data. Not ideal, but better.
I would have to disagree for the city and state that I live in. Google Maps is much more accurate and up to date than OSM and the directions are better too. Not to mention sometimes knowing to route around construction and whatnot. OSM and whether it's better than Google Maps seems to be very region dependent.
I contribute when and where I can but there isn't a huge user base here.
That's bad luck then, friends and I had the opposite experience, with OrganicMaps routing around a road closure where google maps didn't acknowledge it.