I've been using OSM when park maps are not enough, or when I am running across borders (MA conservation lands apparently don't like to make maps that allow you to connect all the trails together).
It depends on how accurate the trails are in your area, though - I seem to get stumped at least once on every long run by something that is not drawn correctly or by additional trails on the ground that don't reflect reality.
Makes for good rogaine training, though...
You want to check the validity of the trails? Strava heat map is a pretty good way in many places.
I have been extremely unimpressed with OSM in our area. I haven’t explored Strava heat maps much, will try it out
Yeah, Jon's been dropping the Strava over the OSM for our scout-oriented scouting trips (last one was to a fantastic area with no trail map support at all). It's good to be married to your own personal mapper. But I haven't felt like bugging him to support my long runs. Maybe when I get up over 15 I'll ask...