Kanvaso Rated 1 out of 5 stars
Since Power Twitter is not working any more against the new twitter, I switched to Kanvaso which is actually better than Power Twitter. You guys might want to try it too. It is http://kanvaso.com. It supports long tweet, image upload, url shortner, mute feature, video viewer, widget, and more. I love it.This review is for a previous version of the add-on (1.52).
Rated 4 out of 5 stars
Power Twitter is nice. I like image uploader, url shortner, and most of features. It makes my tweeting so easy. One thing bothers me is that it requires installing the Addon.
I found one service which is doing almost same thing as Power Twitter but it does not require any installation. It is kanvaso.com. I am comparing between two. I will let you know later which one is better.