I recently installed Thunderbird 3 Beta 3 to test drive it since I’m using Thunderbird 2 as my email client (Outlook is so 2 years ago).
I use Gmail IMAP with Thunderbird as my primary email mainly because of the huge (over 7Gb) email allowance and the uncertainty of what ISP I’ll by using next (I never tie myself down that way). In Beta 3 of Thunderbird 3 the default setting is to download ALL you IMAP mail folders in order to speed things up. Is is just me or is that defeating the purpose of IMAP server based email? I use IMAP because I can access it from multiple clients (for example my home/work PC as well as my Windows Mobile device).
Sure there is benefits to downloading your mail locally, but downloading 7Gb worth of mail on every machine you access your email seems a bit OTT? Luckily you can change this setting to download none or just specified folders. I have set it to only download my Inbox at the moment and that seems to work the best since I have lots of other folders where I file archived emails with videos, pics or important mails.
Another issue I picked up is that it doesn’t seem to pick up sub folders under the root sub folders I created. I think I may still wait for the proper release before using Thunderbird 3 as my primary mail client.