Has anyone tried this with Google Voice?
Personally, even if I had Google Voice I'd find it a hard sell to get me to test it. I don't know of any of these services that I'd feel safe to try. Last time I got suckered into an SMS service it took me a month to figure out how to get rid of it, and about $50 to my phone bill.
Of course, that's because I don't have an SMS allowance in my plan. Should have read the contract closer.
Actually, it only took me a couple hours to research and figure it out, I just didn't move it to my urgent to-do list until the first bill showed up.