OsmAnd and also Organic Maps are great, I have them installed and use them regularly, specially for non-commercial walks, like parks, etc. But Google Maps has much more information on restaurants, bars, shops, hospitals, post offices, pharmacies, hotels, carshops, etc... And the reviews are also priceless when browsing restaurants. Also navigation wise, knowing speed limits, current traffic (I know, I know, the paradox of data sharing), toll-free roads, searching for exact addresses are much much better on Google Maps. For me, of course!