Everyone is raving about the app and I think it introduces some interesting UI/X elements but after playing with it for a few minutes, it just feels cluttered to me. Compare that to both tweetdeck and twitterific which feel great on the iPad...
The only other issue I have is a minor UI gripe. When you click on the run in background button, the progress bar and cancel button for the background tweet covers the back button on the main part of the app. It’s odd that they did that.