Hi! Google Maps will have the advantage in handling huge loads, but I find OSM data much fresher in terms of new developments ( roads, housing estates etc ) and it has much more useful data for pedestrians and cyclists.

I've yet to be impressed by Google Maps' directions for pedestrians, often it sends us along busy roads without sidewalks because there's no commercial incentive to research and include pedestrian-only shortcuts.

I suppose it depends on your userbase.