I’ve come across the best Twitter client for Mac OS X – Nambu. The biggest difference between it and others is because it’s a native Mac app, not an Adobe Air resource hog.
What’s in it? It’s fast, it’s free, it’s configurable, it has features like retweeting, multiple accounts, saved searches, tracking new tweets, etc. And the last but not the least it’s smooth-looking, and fast! Did I say it’s fast?
It also has support for other services, not only Twitter, but do I care. If you are on a Mac there’s absolutely no reason to not use Nambu. Dump the others. Really. Now. Install Nambu.