Works like a charm, kind of. – Track Unfollowers for Twitter Review

App works as advertised. Be careful though when it comes to unfollowing those that "aren't following you back". Be sure and compare the apps results against Twitter. Other than that glitch I've found the app über helpful. Oh, the app Always shows me new followers before Twitter even does, cool unadvertised feature.
Review by BB1Fan on Track Unfollowers for Twitter.