We have added Echofon for Mac to our Echofon family. You can now enjoy the simple and clean beauty of Echofon on your Mac desktop.
As a test user, I have been using Echofon for Mac a while and found out it's better than Tweetie. Basically, I don't like any Apps which use a "drawer". For example, Handbrake is using a drawer odd way and it doesn't make any sense. But, the drawer of Echofon-for-Mac is different. It's pretty useful and innovative. You can stack a conversation or check a user's profile on it. Moreover, you can go back and forward in the drawer history.
One more big feature is "Sync". If you're using a Echofon for iPhone, it sends the last tweet id to their server. When you check the unread tweets from Echofon for Mac (or Echofon for Firefox), it just shows tweets you haven't read. Awesome.
It has almost all functions as a twitter client for Mac. Un-shortening urls, pop up a image window for twitpic and flickr urls, Growl notifications and so on. The only thing I'm missing is that there's no way to read "favorites" of users, include my account. But it's not a big deal for now. I hope it will be implemented soon.
Echofon for Mac is the best twitter client. It's simple and slick. Go http://echofon.com/twitter/mac/ and check it out. It's a beta release so that *you* can improve it by sending your feedback to them.
See also a review on TechCrunch: Echofon (Formerly TwitterFon) Unveils A Simple And Fast Native Mac Twitter Client