From what we have seen so far, Weet for Mac looks like an extremely polished and elegant app to access your Twitter timeline. It seems like the developers did a great job in implementing lots of features, too. The app presents a tabbed interface at the top to let you switch between your timeline, mentions, direct messages, lists and search. The search tab contains your saved searches and trending topics. In the Lists tab, you can subscribe to a new list or check on your existing ones.
Weet's interface is very clean and resembles the iPhone counterpart, great pixels by designer Marcelo Marfil are all over the place. After 5 minutes of usage, I can say I like the subtle tones of the "message bubbles" in the timeline, but I'm not sure about the huge scrollbar you can see in the screenshots. The app comes with multi-account support and lots of other stuff to tweak in the preferences. It's also pretty fast at fetching tweets, although there's no visual notification of refresh. Weet for Mac also features a Mute feature and keyword block functionalities.
Look for a detailed review here on MacStories tomorrow.