I love google voice. I have a used smartphone. I loaded a google voice app on it, and as long as I'm within wifi range (Which always) I can make and recieve phone calls for free. When I'm not in wifi range I use a prepaid tracfone.
If someone calls me while I'm not in wifi range, it's fine, it automatically forwards it to my tracfone. Meaning I pay about $50 per YEAR for the phone service my coworkers pay $70 per month for.
Also google voice will dictate voicemails, and I recieve them as an email. Which is way more conveinent than listening to idiots rambling long voicemails.
Lastly, I can record any incomming calls by pressing 4 during the call. Which is rarely useful, but I did use it once and was glad I had it.
It's just good all the way around.