Not that it was super sucky before. The one glaringly sucky thing about it has been de-suckified, however.
The app now fully supports background app refresh, which means your Gmail messages will be pre-fetched and synced so they’re right there when you open the app—no more annoying pauses while you wait for your inbox to refresh. This feature requires iOS 7, and you’ll also need to turn on background app refresh and notifications (badge or any other type) for the Gmail app.
Note that this can take a toll on your battery life, depending upon how many emails you get every second. Check out this video to see how to turn off background app refresh on the iPhone to save battery life. Note: I have background app refresh turned off for just about every app, but I'll be turning it on for this new Gmail feature. Mark my words. That's not a threat: It's a promise.
Get your mail faster on the Gmail iOS app [Google Blog]