Yes Finally Sprint is allowing you to call people on other networks if you have the "everything Data" plans starting from $69.99.
Yes it gets more limited as the fine print says;
"Sprint may terminate service if (1) more than 800 minutes, (2) a majority of minutes or (3) a majority of kilobytes in a given month are used while roaming.", So “Any Mobile, Anytime” depends on where you are.
But you can cut back on minutes and help others save as well by removing the carrier messages on your voice mail system ("take back the beep campaign" Only Sprint provides this feature).
Sprint (scroll down to read the fine print) via Gizmodo