Outlook Still Better Than Thunderbird
The philosophy behind portable applications appeals to so much that I spend a lot of time evaluating replacements for the non-portable software that I use. Most recently I decided to give Mozilla's Thunderbird a try to see if it was good enough to replace Outlook. Sadly this turned out to not be the case.
When I tried Thunderbird many months (years?) ago I dismissed it almost immediately because it didn't have calendar support. For me, a calendar goes hand-in-hand with e-mail and so it took me all of 15 minutes to conclude that Outlook was still the better application.
What motivated me to try Thunderbird again was a new add-on from Mozilla called Lightning that promised to add calendaring functionality to the Thunderbird interface. Technically this add-on does what it promises, but it misses out on one key piece of functionality -- accepting meeting invites from Outlook. Argh! I also tested out an add-on called LookOut that seemed to suggest it would allow Lightning to accept Outlook invites, but it too was a bust. This lack of meeting invite support is a show-stopper for me so out the window with the whole kit and kaboodle.
As a side note, Thunderbird also does a horrible job of filtering spam even after training it against thousands of spam messages and hundreds of good messages. I've become accustomed to the awesome abilities of the Cloudmark anti-spam Outlook add-on and so anything less just won't do. The folks at Cloudmark do have a beta version of their anti-spam tool for Thunderbird, but I couldn't get it to work. That's strike two against Thunderbird.
So Outlook is still my preferred e-mail and calendaring client which in itself isn't bad. I just wish it was portable!