Google is much better when it comes to both places and addresses, but OpenStreetMap is improving rapidly and you can get great coverage in most big cities. Also in theory you could source the POI data from some other place and overlay that on top of OSM street data.
Google used to be much better in terms of ease of use, but with players like MapBox that has changed dramatically. Its so pleasant these days to use OSM to make a mapping product -- try out cartodb.com or mapbox.com just for kicks.
And the big plus of OSM of course is that you can pick and choose what data you want to render, what you want to do with it (my fav new example is this scooter routing engine that takes into account the hills in SF while routing --> https://www.mapbox.com/blog/launching-smart-directions/)
As for "hard data" -- here are a couple of studies that compare OSM with private map providers
For example, many cities in OSM have virtually perfect address geocoding because some random person pestered their local government to openly release a dump of addresses and their coordinates, whereas Google is just guessing at house numbers.