The killer feature of Organic Maps is that you can download the maps for the entire world (yay OSM!) and not have to depend on signal or having a data plan.
Super important for intentional travel or nature (National parks often have no signal).
It's blazing fast — far snappier than other map apps I've used. And OSM data is better than Google's for hiking and biking.
The POI database isn't as detailed, and you wouldn't use it to find an espresso shop near you (...yet). But it's much better as a map app.