Originally a Nook exclusive before coming to Android last fall, the open source, Google Maps alternative is finally coming to iOS, which is arguably the most alternative-map-app-needing platform of them all.
What does it do?
Pulls data from OpenStreetMap, a worldwide open source mapping project to create a totally interactive map with consistent, free updates. In addition to the same features you've come to depend on (directions, location finder, zoom, sharing, etc.), you can also chose from a variety of map styles to suit your needs (such as night and outdoor), all within a map that's accuracy will continue to increase as more people continue to use it.
Why do we like it?
Being able to use the maps both on and offline is a major plus, especially since you often need a map app the most when you find yourself in those remote, off-the-beaten path locations that so rarely offer cell service. But just because your maps are stored on your mobile device doesn't mean it's going to eat up space; ForeverMap2 uses an advanced map compression technology that severely limits how much space the app will take up. Plus, to celebrate launch day, you can download the service for a limited time for $1 as opposed to the normal $3.
ForeverMap2: iOS/$1, $3
The Best: Offline use
The Worst: None