When I switched from fulltime Windows to fulltime Mac a few months back, I went right from Outlook 2003 on Windows XP to Thunderbird on Mac OS X, with only a slight pitstop at Mail.app. Now with the news that Mozilla is considering inching itself out of the mail biz, I’m wondering if I gave Apple’s Mail a fair shake. I also considered web-based email. Still not interested. I like having my email in separate windows that aren’t dependent on the browser.

But I do keep all my email online. I rely on Island Email‘s IMAP server. This makes switching local clients easy. No messages to transfer. With IMAP, you can organize your email in folders right on the server. An email read in a browser or Thunderbird comes into Apple mail already read. Delete in one client or move to a sub-folder, it’s that way in the other client. Island’s IMAP server is excellent. If I can help it, I’ll never go back to POP3. I have around 5,000 messages saved on the server from April 2007 forward. I’ve also been forwarding all my email to Gmail for over 2 years, for backup purposes.

Spam filtering is not an issue since both applications use the wonderful (98.3% correct and counting) SpamSieve.

After a few hours I can say that Mail 2 does have advantages I never appreciated before over Thunderbird:

• It’s much, much faster for searching. In Thunderbird, searching for a word or phrase that appears within the body of a message in a folder with over 5,000 messages saved remotely is very painful. Plus I had to know which folder I was searching. Mail easily searches multiple folders, locally or remote.
• Messages are so much prettier. Thunderbird has improved font and image rendering, but it doesn’t come close to Mail.
• Growl support is better. I kept getting double notifications in Thunderbird. Mail notifications work very well, and I can tell it to ignore the spam folder.
• Smart Mailboxes are handy.
• In Thunderbird, opening an attachment downloads it to the desktop. In Mail, the download is saved to a “Mail Downloads” folder keeping the desktop a little neater. If I open the same attachment from an email again, it opens the same file I already saved locally. Thunderbird would download it again with a filename-1.doc title. At the end of the day, it wouldn’t be uncommon to find 50+ files on the desktop.
• I can use Maildrop to work with Salesforce data in email. Works beautifully.
• One more thing: message threading. This morning I clicked on a message and was getting ready to reply, when I noticed other  messages in my inbox were highlighted, saving me from answering a question that was already answered. I forgot about this feature. Helpful.

The downside:

• I can’t stand iCal. That’s not changing. I like having the calendar integrated right in the window with Lightning (which synced with Google Calendar).
• Identities. This is going to be the biggest challenge. I have 3 different email addresses that all go to the same Island Email account. In Thunderbird, I was able to set up identities so when I replied to a message, it would select the identity based on the “To:” field of the message I was replying to. In Mail, I can separate the 3 email addresses with commas and that way I can select from them when I reply, but I have to do that manually and change the signature each time. This is a pain and I’m sure I’ll forget and make mistakes (I made the default my work address, just in case). I’m hoping there’s a script or something somewhere that can duplicate this functionality that I miss. Anyone know?

Maybe Mail in Leopard will fix this shortcoming. For now, I’m willing to stick with Mail and see if I can get used to it.