Twitter changed "favorites" stars into "like" hearts yesterday and the Internet BLEW RIGHT UP. Twitter's official announcement can be read here. They seem quite positive about it, so if you only read the official word and didn't track the reaction, you might call this a success.
Reactions elsewhere are mixed. Twitter's earnings for the third-quarter seem depressing, and Deadspin writes that this change from favs to likes is one of several that the company is making in an attempt to "save itself." There's a discussion thread on WebmasterWorld where a user named keyplyr says about as much.
Finally, The Verge has a short article from a user perspective. I had NO idea that favs had their own culture (a passive-aggressive one, of course, because this is social media) or that they'd be missed this much. But then again, if Twitter believes that this change can save its business...I suppose it's not unreasonable to expect an equally strong set of reactions and expectations from the community.