As for the navigation data in TT maps and OSM maps for Germany university Heidelberg found in a study in 2012, that OSM maps of 2011 lacked only 9% to TT maps at that time. They exspected however, that OSM maps for Germany would catch up to TT by the end of 2012. Since it is 2021 now, at least Germany OSM maps should be equal to TT maps. And I would expect, that for many other countries this is the same.
Maybe OSM have all the details (or even more) - but that's only one aspect ...
I have a few more navigation systems running - in routing for motor vehicle (motorbike, truck) the commercial systems working with map data from TomTom or HERE create much better routes. Especially when I set "no highways, no tollroads" all OSM-based system (NavFree, OsmAnd, Calimoto) give me very strange routes. Classification of roads seems to be very strange sometimes and different from one corner to the next. New roads or other changes (new roundabout for example) often appear faster in OSM than in commercial maps - but you can't rely on this.
As pedestrian I prefer OSM - the commercial map data are made for road routing and miss a lot of footpathes.
And commercial map data contain lots of old and outdated POI - looking for a gas station and driving to a point where the gas station closed ten years ago can be very annoying ...
So for routing from here to there I use commercial programs on my navigation system. When I am there and look for a restaurant or a campsite or a gas station, I use NavFree with OSM (because my navigation system is running on WindowsCE and NavFree still supports Win).