Since I had some time, I installed Thunderbird 3.3a2 aka Miramar. Upon the first start-up I was prompted to setup my email account. The process went smoothly as like in Thunderbird 3.1, setup should be able to auto-detect the account settings based on the email address you put in. Since all my email accounts are IMAP, I had Miramar synced with Thunderbird 3.1 running on my Windows 7 and Ubuntu machines. Took a couple minutes of playing around in the View menu to get the layout the way I preferred.
As you can see from the About screen, Mozilla Messaging did get a bit creative in the design here. The program icon/logo is also the surf board in the sun. Sadly though, I can not the same for the rest of the UI. Yes it is clean, but a bit ‘too clean’ (see below image). At least in Thunderbird 3.1 and older the buttons had some color to them. I suppose it could be better if Personas could be integrated in like with Thunderbird 3.1. However, at this time it does not look like Personas are going to work with Miramar.
Much like Thunderbird 3.1, there are a handful (even less with Miramar) of add-ons which can be installed using the built-in add-ons manager. In the case of Miramar the only compatible add-on was AdBlock Plus.
Now it is important to realize Miramar/Thunderbird 3.3 is a while away from final release. After all this is only the second developmental release. Do have to admit it seems really stable. I’ll keep an eye on this as it progresses through the Alphas then to Betas and then Release Candidates.