The Twitter app on Google TV takes a little getting used to but once you get the hang of it, it is actually pretty nice.
Here is a little tip that I just discovered: In a tweet that includes a Twitter user, a hashtag or a web link, you just have to double-click that selection and you will bring up a new page with more details.
Example would be in a tweet that has "@googletv rocks, go to www.google.com/tv to check it out! #googlerocks" all you need to do is double click @googletv - it brings up the user info for that name, double click #googlerocks and it will bring up all the tweets that contain that hashtag, and by double clicking the www.google.com/tv will take you outside of Twitter and open up that webpage in the Chrome browser. All in all I think it is pretty slick.
So give it a shot... and enjoy!