It’s a free alpha, and I am so glad it is here. Twitter’s official Mac client is outdated by about two years. Scrolling performance isn’t great on my iMac, but I would expect this will get sorted out by final release. For now, I’ll probably stick to the official client, but I am really excited to switch when 1.0 actually ships.
The main draw, iCloud integration between Tweetbot for iOS and Tweetbot for Mac, is not yet included as only App Store apps are allowed to use iCloud. Obviously, this will be included when the actual version is released.