Originally Posted by sheeep

The Gmail application has its own look-and-feel which is totally different from the built-in mail client. In fact, the app looks like the full PC version in miniature. If you like the Gmail interface, you will definitely like the app.

Advantages over BIS/BES would be:
- full "labels" (folders) support
- you can "star" (mark) messages
- full search capabilities (you can search ALL your mail in your Gmail account)
- access to your Gmail addressbook
- way better looks (in my opinion)

Disadvantages:
- you can't send attachments (reading is supported though)
- new mail arrives a bit slower because the application uses a poll interval of 20 minutes instead of push mail
- the small "envelope" that shows up when new BIS mail, SMS etc. arrive is missing yet (apart from that, there is full notification support however)
- you can't send Gmail mail from the addressbook


Overall, I really like the Gmail app. I guess I would even use it instead of BIS if I had that (my provider doesn't offer it) but as I don't I can't tell for sure ;).