I finally decided to migrate all my mails to evolution. I like Thunderbird, but the problem there is the poor integration into gnome and some bugs in the calendar (especially with google calendars). I hope that the Thunderbird development will continue and maybe put some effort in integrating Thunderbird into gnome.
The migration took me some days...the first step was to get all my pop mails from my main freemail account into gmail where I can get them via imap. Gmail is really nice to aggregate various mail accounts because it can get your mails via pop from every server you want!
Just be careful not to forward all the messages you get on gmail to the account you want to import :D You will get some nice messages from google that they are sorry, but they have given up because of a mail loop. I guess the message is worth doing it anyway ;)
Some thoughts about evolution:
What I like about evolution is the build in calendar and how Evolution integrates into gnome. Thats really great.
But I'm a little bit disappointed by Evolutions ui. I am used to Thunderbird and it could be that I just need some time to get used to Evolution, but as a "first user" the ui and the menus are quite confusing.
One example is the creation of a new appointment. I've never seen a bigger button-salad: The "Save", "Print" and "Close" buttons are somehow "grouped" together. There is a toggle button ("Show time as busy") in between of some normal buttons and the "Alarms" button opens a new window which uses 7/10 of the space for the "custom" alarm which is only one of the options in the dropdown list (and maybe the most rarely used one).
Another example is the compose mail window: half of the space of the window is used for other things then the text of the email, which should be the central part of the ui.
The notification area at the bottom of the main window is confusing too, when there are more things going on you can watch the buttons and labels fly around like in one of the good old videos of the 90's.
I really don't want to piss someone off: I respect the work everyone did for Evolution and I do understand as well that it's not easy to design complex ui's.
Bits and pieces about free software and various other things.