I never used the led notification, but the audio notification still works. I just tried it out with my Touchdown mail client which pushes mail from my Exchange server at work.
So with wifi set to never sleep, I get a notification tone as soon as I get an email regardless of whether the screen is off. However, if wifi is set to go to sleep whenever the screen is off then if I get an email while the screen is off I will not get the notification tone until I turn the screen back on.
This behaviour defeats the purpose of having push email, since I have to check my phone to see if I have email rather than my phone telling me when I have email.
So with wifi set to never sleep, I get a notification tone as soon as I get an email regardless of whether the screen is off. However, if wifi is set to go to sleep whenever the screen is off then if I get an email while the screen is off I will not get the notification tone until I turn the screen back on.
This behaviour defeats the purpose of having push email, since I have to check my phone to see if I have email rather than my phone telling me when I have email.
And 2G + 3G is not only for data. It can be for voice also... What's the harm in trying? If it helps, good... If it doesn't, too bad we'll find another solution (Like the kernel)...