I'm using it, and really like it. Since I just moved it gave me the ability to have a local number here in DC without having to get rid of my old number that everyone already has. The free text messaging doesn't matter to me (we have unlimited text messaging for our AT&T family plan already, and unless everyone switching to using Google Voice there's no point in canceling that), but the voicemail transcripts are awesome, and the fact that you can very easily screen calls and also set how to handle calls from particular numbers including sending them straight to voicemail or even just blocking them means I don't really need to worry about giving out my GV number freely.
The only thing that would make it better is if it would fully integrate with my iPhone the way it does on an Android phone. I'm actually seriously considering switching because of that.