The first time I read about someone giving up their RSS feeds for Twitter feeds was about a month ago. I recovered from the shock quickly, but am not likely to make the move. Ever.
Twitter is an instant-gratification machine. No doubt, I have found articles and information on Twitter before it appears on RSS, and I've gotten info I would have not found otherwise. However, the main drawback of Twitter is that it's happening NOW. If I have a busy day and want to catch up, Twitter simply is not going to offer me a solution. If I want to catch up on just what's important to me, again, Twitter and its accompanying clients are inadequate.
RSS feeds are far superior for batch-mode newsing. I've got the key information under more than one category (tag) so I can quickly see what I've missed. RSS automatically displays at a glance what I usually read and what I usually ignore (427 unread posts -- obviously something I don't care much about).
And threading, where would I be without threading? On Twitter, of course.
Other than my personal preference, though, I have to ask myself what it means when so many people are talking about Twitter as an alternative to other news sources. Truthfully, if you are more than 200 tweets behind, you aren't going to catch up on your tweets. In other words, if you sleep or have meetings, you start to fall behind. If you don't tweet on the sabbath (hey, some of us don't), you miss information.
One issue with this is what it means culturally, when you have a group of people who basically have committed themselves to almost-constant connectivity. On top of that, it's non-threaded connectivity. This marks a major change in attention span. Firstly, if it's not happening now, it's not happening. Secondly, if you are online in this way, you are constantly dealing with interruption. Any task that requires more than half an hour of concentration is a challenge.
In other words, you are wasting a tremendous amount of time. I've seen a lot of apologists about how Twitter is useful for business, and how twitterers are more effective, etc. I don't find that particularly likely.
The main issue, in my eyes, is what something like Twitter does to the culture. What does it do for the culture when you need to be updated all the time, and anything that happened over 2 hours ago is passe? What does it mean that if you go to sleep, you are missing several hours of your important updates? Moreover, how can you enjoy anything when you need constant update?
I use twitter, a couple of minutes a day, usually, and definitely no more than half an hour a day. Let my friends say I'm old-fashioned or out-of-date. Me and my RSS will just have to live with it.