Based on what is said in that news story you linked to, they don't seem to be aiming at SO or PCM. Chatr is going for the $45/month unlimited talk-and-text market, with non-subsidized phones. Unlikely to woo away any SpeakOut customers, unless your usage has risen to the point where SpeakOut is no longer the optimum plan for you.
For me, SpeakOut's 365-day expiries are a perfect match for my requirements. I'd be surpised if any other company would try to capture some of this market from SO — there can't be much money to be made in this low-usage niche.