Originally Posted by Berrymedic20
I'm not debating that the **POP** BIS setup for gmail works instantaneously. This is what I've been using, and it does work. It lacks the following, however: messages read on the BB still show as new on the server; deletions on the server don't delete on the BB. That means that if I'm checking my mail online, I have to go through and mark everything read. Things I delete online I have to back onto the BB and delete manually. This is just annoying... an inconvenience. The system works for its essential purpose, but is not as useful as it easily could be.
With IMAP (using IDLE), the emails are not only pushed instantaneously, but blackberry and webmail are sync'd perfectly, all the time. Trust me, when you've had this, you don't want to take a step back to POP. My treo did this flawlessly, and I can't see why Blackberry wouldn't either.
GMail integration with BIS does not utilize POP protocols. As RIM did with Yahoo, they worked with Google to integrate their PUSH technology into their mail system. I believe BIS 2.5 will unleash the full two-way synchronization between GMail and BIS (so your deletions and read/unread status reconciliations will go both ways). Yahoo is currently two-way synchronization, as mentioned above.
...not to mention that you get your Calendar with these services, which ChatterMail did not do on the Treo. Rumors circulating say that Contacts synchronization will soon come, as well.
...or you could look at the BlackBerry Unite! product for use on your home computer.