Recently, I used Google Voice Chat to call my brother who lives in New Mexico, USA from my home here in the North Okanagan Valley of British Columbia, Canada. We talked for quite a while via PC-to-PC calling (we both use headsets). I have to say, I was very impressed with the voice quality of the call. I don't recall a single glitch, latency, echo, or dropped packet, etc. It was a perfect crystal clear voice conversation for maybe 45 minutes or so. And, of course the call was free.
Personally, I now prefer to use Google's Gmail Voice and Video Chat rather than Skype. While, there are probably a lot more people who know and use Skype, I have been an avid user of Gmail since its infancy back in 2004.
Before Google Voice and Video Chat was launched, Google launched "Google Talk", which was their initial attempt to compete with Skype, back around 2005/2006. I used Google Talk and liked it very much. It was a much smaller and lightweight application than Skype. But, it wasn't as mature yet as Skype was at that time.
I was actually one of the early adopters of Skype back in 2003/2004. It was only one of a very few desktop VoIP applications available. The voice quality back then was a very much touch and go proposition. But, Skype slowly and surely improved their voice quality with each incremental update over the months and years. Back then they also allowed free calls to land-lines and mobile phones (but that is now ancient history).
One of my biggest complaints about Skype (especially in the earlier days) had always been that it was a relatively large application using lots of memory, system resources, Internet bandwidth (back in those days, Internet bandwidth was at a premium and Skype tended to suck it up). And, it was a separate application that had to be running all the time if I wanted to be available for incoming Skype calls. And, in all honesty, I received very few calls via Skype (I was a lone VoIP geek dabbling in VoIP with no one to talk to but Skype's Echo Server). Actually, I did talk to my brother in NM from time to time, but that was only once every few months. So, it seemed like a waste of system resources to keep Skype running all the time. And, of course, there was also the fear of becoming a "Skype Super Node".
Bearing in mind, I always had my browser-based Gmail running all the time and sometimes the Google Talk app, too. So, I was really pleased when Google announced the implementation of Google Voice into Gmail. Since then, I had no more reason to use Google Talk as a separate VoIP application. Basically, I could do the same thing from within my Google Apps version of Gmail, which I have open all the time anyway.
I rarely use Skype anymore since they stopped providing free calls to USA/Canada land-lines and mobile phones. While, for the past two years or so, Google has been providing free calls to USA/Canada land-lines and mobiles. So, there is no contest there from a cost perspective.
Currently, Google Voice is still allowing free calls to land-lines/mobiles throughout USA/Canada until the end of 2012. I'm very curious to find out what their plans are for 2013.