There are still some problems with gmail push at the moment as far as stability and speed go. Attachments are also not working as of two days ago (the one issue google has acknowledged and is attempting to fix.)
For those of you looking for an alternative that works perfectly NOW, try the instructions posted in the following thread for setting up Gmail as an IMAP (which has been out for over a year now and is stable) account with push using IMAP IDLE in this thread:
http://forum.ppcgeeks.com/showthread...88#post1219288
Configuring gmail this way will also allow you to connect to both your work Exchange server and gmail... and you'll be able to push mail from both at the same time.
Please direct your questions about the Gmail IMAP and IMAP Pusher Service to that post, I'll be glad to help with any questions.
Thanks and good luck!