Not only does Google’s Maps app for iOS generally provide better mapping data, but it also includes some nifty UI features, including the ability to zoom in and out on a map with a single finger. This is a particularly great feature for one-handed operation on an iPhone or iPod touch, although it works in the iPad version too.
Simply double-tap and hold your finger down anywhere on the map and then slide your finger up to zoom out or down to zoom back in. A single tap-and-hold gesture after releasing your finger returns you to normal panning mode.
It can be a really cool way to navigate around your maps once you get the hang of it..