For those of you who have not yet done so and are considering switching e-mail clients, what works for me is to have an online e-mail account such as hotmail or gmail setup to retrieve all your emails from all your accounts. Or even just that account. Set that account up in your current e-mail client if you haven't already. Synchronize with your online account and when you are ready, setup your online account in your new e-mail client and then synchronize that. Voila, you have everything in your new email client you had in your old client.

Another advantage is that your e-mail can be synchronized across all platforms. Yes, even your phone. I don't have a smart phone but I do have an iPod. I set up gmail using the included email client on the iPod and now I get all my emails on the iPod if I am so inclined. This works with Evolution and Thunderbird as well. This may not work for everybody. It depends on your email requirements. I have not done it with a work e-mail but I haven't had the need. I have about four email accounts and two computers. Three if I count the iPod. They all remain synchronized with each other and if I don't happen to have a computer with me I can still get my email through any computer connected to the internet.