Editors' note: This review was updated June 4, 2013, with the latest features in version 2.3.14159.
Gmail for iOS, Google's official e-mail client for iOS, has evolved into a strong offering. The latest version adds new notification options and a brand new way to sort your inbox with tabs.
Obviously, the Mail app that comes with your iPhone lets you connect to Gmail accounts, but with the official app from Google you'll get a few more options that you may have come to rely on in using Gmail. Starting with the basics, once you're logged in to your account, you'll get a view of your inbox with a Menu button in the upper left and a "compose e-mail" button in the upper right. Just below that (and above your inbox), there's a search field you can use to search all your e-mail.
As you would expect, Gmail for iOS has most of the basic tools found in the browser-based version. You can read mail and browse through threaded conversations, keep track of important messages in a priority inbox, and organize your mail using starred messages, labels, and archive features. Other features include autocompleting contact names as you type, sending and receiving attachments, an infinite scrolling inbox, and Gmail's excellent search functions. You also can use and manage multiple Gmail accounts; respond to Google Calendar invites within e-mail messages; and search features include predictive text as you type for quick inbox searches.