Tweetbot is a full-featured Twitter app for the Mac based on the award-winning apps for iPhone and iPad. With retina support, sync via iCloud, and multiple column views, Tweetbot is the premier Twitter app for the Mac.
Instant buy. It may seem a bit expensive for a Twitter client but trust me, it’s worth every penny. I like how Gruber puts it:
$20 for a Twitter client? Damn straight. Screw the race to the bottom. I’m happy to pay for quality work.