I agree, it works well for me. I'm abroad 11 months of the year. This setup permits me to receive calls on a US number without paying international fees - even better it is now the number that all my contacts already have.
Also, the porting option works too. Again, for me, being setup with google voice means I can land in the US and see which provider will give me the cheapest PAYG sim card for the next week, buy it and not have to maintain a relationship (i.e. minimum balance, usage, or monthly bill) with them to keep my number when I leave again.
I don't think it is for everyone, and you need to think if it's right for you. Alot of the upside (voicemail transcription, etc) can be had without moving your number. For those of you who do decide to go ahead with it, it's a fairy easy process from my experience.
