Like the article states, I think Tweetdeck is more powerful and more useful than normal Twitter. You can see a much broader and deeper view of the topics you are interested in, and see it both at a glance and deeply if you decide to dig in. It's also excellent for watching trends in real time (such as many people tweeting about a conference).

Your normal feed forces you into a much more "all or nothing" approach. Someone who often tweets useful stuff but also lots of noise, you either have to put up with the noise or miss their good stuff. In Tweetdeck, just their good stuff shows up.