I use Google Voice as well. For messaging people it works very well, especially if you have messages pushed to your phone so they show up just like normal text messages.
The problem with it though is you can't text to any of the short code numbers that companies use. They simple don't work with Google Voice (or any of the other free SMS services).
The other problem, at least on the iPhone, is that when you text someone it defaults to SMS, not Google Voice. With iOS 5, it will default to iMessage, but only if the person you are texting has an iPhone. If not it uses SMS. So to text using Google Voice you have to remember to actually open the app. I believe Android can use Google Voice by default (obviously).--
The Comcast Disney Avatar has been retired.