Mail Client Compatibility?

I use Apple Mail and enjoy its compatibility as the default mail client integrating with other Apple applications such as iPhoto, and syncing with other devices through Mobileme. If I switch to another email client such as Thunderbird, and set it as my default email client, will I retain all the integration among apps and syncing, or will I lose something?

I use Thunderbird strictly as an NNTP newsreader and have not dug into its mail capabilities all that much. However, doing some reading on the Mozilla site leads me to believe it can sync with other devices using IMAP. Not sure if that's what you're looking for, but here's the LINK. See what you think.