with a limited battery life coupled with the limit of a smart phone battery and at that price point I can't imagine relying on this over a traditional walkie talkie.
I think this could work, outdoors but also when travelling with a small group avoiding huge roaming charges. Battery life should be ok, I don't think it's designed for chatting away just basic communication.
Seems extremely similar to the Gotenna (which is shipping) [1].<p>[1] <a href="http://www.gotenna.com/" rel="nofollow">http://www.gotenna.com/</a>