Gmail has updated its controversial Gmail App for iOS. These are the updates -
You can set a custom signature for your mobile messages and a vacation responder, both available through the gear icon at the top of the menu view.
Also you can now open up a canvas and scribble a message that will be attached to your email. iPad users can give it a try.
Another update is about change of the notification sound that it’s easier to distinguish when you've received an email.BUT I haven’t heard any Sound Notifications when a new mail arrives. Checked in General Settings also still the problem persists. Gmail Please look into it.
UPDATE 16/12/11 : Since morning I can hear the ‘Ding’ when a new Mail arrives. Seems it has been corrected.