The Telcel web site has changed, the details of this rate are now at
http://telcel.com/personas/telefonia...s-sin-frontera
Outbound calls are a little cheaper and do still vary a bit depending on recharge level, from 0.98 to 1.49 pesos (6 to 9c/min), to call from anywhere in North America to anywhere in North America. Data and text unchanged.
Incoming calls and incoming texts are still free in all three countries. (I don't know of any other pay-as-you-go without monthly fees that has free incoming calls in all three countries).
Roaming is normally on T-Mobile, but I have found now that AT&T also works, including for 3G data (but not LTE). I have to reboot the phone for it to accept it, can't just select a new network.
Sims: Telcel MX, T-Mobile US, Virgin Mobile UK, Orange UK, Knowroaming
Voip: Localphone UK, Anveo US, Google Voice