Well, that wasn't too hard -- install TBird for Windows, import Outlook email, copy folders from Windows to Linux, reset permissions. It all seems to be there. Would have been nice to be able to save a step, but, oh well.

You're right, Thunderbird does bear quite a resemblance to Outlook, down to the color scheme. (Mozilla Mail is kind of a drab blue-gray.)

Maybe it's all about what you're used to, but I really prefer having a local email client that grabs all the email off the server. Web-based interfaces tend to show you a lot of advertising and don't have as many features as local clients, and you're trusting someone, somewhere, to store your email for you over the long term. (Yes, I'm trusting my ISP to store it for me, too, but I try to download it every day.)