Harrkev, would you mind elaborating a bit on what you mean by "not reliable"? Do you mean in terms of range?

I just think DirectTalk is an interesting option for people who want to have a means of short-range communications with people who may not want to carry a separate two-way radio as EDC, like a spouse or family members. My wife will not carry a FRS/GMRS radio in her purse, but she probably wouldn't mind carrying a Nextel phone with her, which could prove valuable in a situation where cell service is suddenly down or overwhelmed, like after an earthquake.

Still waiting to see if anyone's had any real world experience using it, though.