It's working great!
I don't recall how long it's actually been, but for some time now I've been using Twitter exclusively as a source of news and reading, having completely abandoned RSS (e.g., Google Reader, etc.). So far, it's been working great.
I have a finely tuned set of a few less than 300 Twitter accounts that I follow. Adding more usually just adds noise. Occasionally, I'll try additional accounts but end up removing them later. I take that as a sign that my list is just right. It's also important to note that this set of tweeters are almost all people (or robots) that repost links. There are almost no “Now I'm eating a donut” posters. A number of the accounts are for official sites like @mashable or @slashdot. Instead of going to some destination web sites like I used to, I just read the summaries on Twitter, then click in to read the links (stories) that are interesting.
I also have a set of lists so I can read just News, Tech stories, etc., if I don't want to read my complete stream. The most important thing that lists do is allow reading back farther than just the past few minutes. It's a characteristic of the real-time nature of Twitter that, if you read during certain times of the day, you get a particular sample of your list of followees. That sample limits who and what you actually see. However, reading back through a list, e.g., through a news list, allows reading past that “latest” horizon and results in a better sample of the news of the day.