Hootsuite, Tweetbot etc offer searching and muting based on tweet content. Tweetdig offers the ability to filter based on a wide range of criteria (such as filtering out tweets from a specific user like you mentioned). That's our differentiating factor.
Thanks for the comments on hiding add/edit/manage under configuration. We'll take a look at where we could fit them into the interface.
We're very interested in the user experience, and we've improved it a lot over the last few weeks. It still needs a lot of work, but we're finding that the first thing new users see is the design. I think to get them past that, we need to take a look at the UI. People don't seem willing to give things a try if it doesn't look pretty, no matter how easy it is to use.