Google have at last released an official Gmail app for the iOS platform.
The whole Gmail experience has been made touch friendly and you can access all parts of Gmail like you can on a browser version, for example your Priority Inbox. You get push notifications right on your homescreen like you do with other mail accounts so you can view your emails as they come. Google have included their search feature, letting you search for anything and everything within your inbox. You also get a threaded view of all your mail so it looks more like IM instead of email, making it flow better.
On the iPad you get the split view so you have emails on one side and the actual email content on the other.