Depends heavily on the set of people you follow. I've found it to be a great source of news, and I typically see news show up there hours to days before I see it show up in places like HN.
That said, it took months to get my feed to where it is today. It's not easy for each person to find the mix of accounts that is best for them. My recommendation is, be fast to follow folks who look interesting, and fast to unfollow folks if they are boring or you don't like them. When you find folks you like, see who they retweet, reply to, follow, etc. and follow all those folks to see what you think.
I guess you can find other people's lists and follow them? E.g. a sports journalist's sports lists etc. I have not tried to do that so not sure if there are hurdles to overcome. And maybe someone can aggregate these public lists for others to find/follow?
It's called ESPN.
I have no idea how people follow more than say a hundred people profitably.
What I find awful is that HN and Reddit save me time by sorting out low-quality content, while on Twitter you're the one that has to work hard to do it (if you can), and Twitter itself just adds more noise in the meantime.
This is particularly relevant for hyper-local media which basically has zero media footprint outside of dead-tree newspapers and talk radio.
Basically: follow your city councilor on Twitter. Start from there.
Twitter is what you make it. I'm sincerely worried their VC backed top heavy company is going to topple over and carry with it to oblivion a service that could probably run on 1/20th of it's infrastructure.
But I see it as a way to keep track of what a columnist, journalist, or public figure is doing.
I've used it for a while, and what I got is that it's goos for (and people use it) to spam others about your projects or show off. However, if you try to use it to get news or updates on anything it is the least efficient, most stressful thing I've ever used.
I see Twitter as a good tool for outages, natural disasters, and protests. That's pretty much it.