The most popular mapping programs, like Google Maps and Apple Maps, are great as long as you have a data connection on your iOS device. But if you are a traveler and get off the beaten path, you can be stuck with a blank screen on your iPhone or iPad.
Maps with Me Pro solves that problem, giving you access to "everywhere" for a one-time US$3.99 purchase.
The app covers 345 countries and islands, and your one-time payment lets you download maps for any of those locations. Also included is a very complete point-of-interest (POI) database. As noted, the app works without any internet connection, and maps draw quickly and zoom quickly. The app supports bookmarks and location sharing, so you can send your location to a friend (for that, you'll need a data connection, of course).
I live in Arizona, so I downloaded the Arizona map for testing. That took about 30 seconds over WiFi, and if I was going on a trip, I would just download maps for my destination prior to leaving.
Using Maps With Me Pro is simple, but it is not a navigation app in the traditional sense. If you find a museum you want to visit, for example, you will see your location and the museum on the map, but you won't get turn-by-turn directions. The map keeps your location on screen when you are moving, so it's not to difficult to get somewhere.
Zooming is infinite: As you zoom out, you will see the whole world, and as you zoom in, you will get some details. But if you zoom in even more, you'll be asked to download the appropriate map. I gave the app a tough test: Pitcairn Island, which figured in the famous Mutiny on the Bounty story. As I zoomed in, I was asked to download a map, and within a couple of seconds I had a detailed view of the streets on that small island. Google Maps and Apple Maps both show the island, but it is blank -- without a single road.