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.
Then there was a small analysis in Germany in 2012, but obviously a lot has changed since then.
http://www.mdpi.com/1999-5903/4/1/1 (Or just have a look at the images on the German article: http://neis-one.org/2012/01/osm-germany-2007-2011/)
The most notable difference in terms of quality that I have personally noticed is that the geocoding on the OSM side of things is of wildly variable. The Cloudmade v1 Geocoding API was simpler and returned better results that the Cloudmade v2 API, but the data returned in v1 had less detail that the data returned in v2.
Mapquest offer a licensed data geocode and an open data geocode. The licensed data geocode, as you would expect, returns better results than the open data geocode but still fell short of both the ease of use and accuracy of the v1 Cloudmade geocode.
The kicker in all of this is that Cloudmade recently changed the way they choose to do business. That meant that my internal application wouldn't generate enough hits to the the Cloudmade servers to continue to keep the account open. We were literally in a situation of wanting to throw a small chunk of money at Cloudmade but because we couldn't meet a seemingly arbitrary lower limit we couldn't, abandoned Cloudmade and moved everything across to Mapquest.
Also I'd just like to call out that Leaflet.js is a fantastic library to use and allows us to do everything we want to do to the maps with an absolute minimum of fuss. We are looking at adding internal floor plans to some of the maps and I managed to throw together a PoC in leaflet.js that is looking like it would easily support this with a minimum of fuss.
If you just want to display a vague map of a major metropolitan area it's ok. But as soon as you need to actually find an address, you're out of luck.
Especially Germany and the U.K., but there are other active communities.
Also, in the U.S., the Nominatim instance setup on openstreetmap.org mostly falls back to address range data imported from Tiger. That data isn't really part of OSM. It gives great coverage, but there are some limits to the accuracy.
But the internet is global. It might work correctly for you when testing, but somebody in another country finds your app utterly useless.
Even if Google Maps has worse data for some areas than OSM, globally it's far more consistent.
Given that there's far, far cheaper options for mapping than Google while still providing excellent data (ArcGIS comes to mind), if you're building a commercial product with an international market in mind you're still better off using a commercial GIS solution
This appears to be based on a misunderstanding; the OSM project isn't an app released by a company, instead it's a global community creating a map dataset, somewhat similar to Wikipedia.
If the data in your country or local area isn't good, then please consider becoming a contributor to OSM and edit the map. By making the OSM better, you can help solve those consistency problems and improve the experience for the growing number of people who are using it - whether directly or via companies like DoubleMap.
Being a contributor is nice and fuzzy, but not a commercially viable option. If my customer says "I can't find this town on the map", I'm hardly going to tell them to drive out and map it themselves.
Who knows what will happen in Australia, but a thing I see happening in the U.S. is people starting to use OSM for whatever and then investing effort in fixing their immediate problems. So there is some sort of hand wavy tipping point that has been reached.
And when it comes to websites there are even more of those.
Not to mention that more and more apps use data that only OSM provides.