Although Google has introduced its own solution for pushing Gmail messages to your iPhone's in-box, this application still has plenty to offer. GPush alerts you to incoming Gmail messages with a red icon badge, a chime, and a semitransparent alert window that reads the sender's name and the subject line (you can change these in the Notification settings.) The alert bubble presents you with two options: to close the notification, or open the GPush app to view the new message in GPush's Gmail in-box, albeit rather slowly. Since GPush is giving you access to Google's mobile Gmail site for iPhones, you'll be able to do anything with that e-mail that you could do from the Safari browser. The notification bubble and quick link to an in-box are not offered as part of Google's push solution at the time of writing.
When it comes to performance, at least as far as our iPhone is concerned, GPush finds new messages faster than Google's push service about half the time. While the new Gmail in-box feature is exactly what we asked for, having GPush open to the Gmail in-box tab took longer than it should. We hope to see this speed up in a future release.
Note that your phone frequently switching between Wi-Fi and 3G data could disrupt GPush's service. During these moments of instability, GPush will queue the new messages for notifications. When the iPhone regains its service, GPush sends out only the most recent notification, an Apple limitation to keep alerts from flooding your screen.