Apple murders this space.<p>iMessage does all of the stuff whatsapp does regarding groups, etc AND it has a killer desktop client (the mac). Not only that but my non iMesssage text messages are proxied to my mac as well. I can communicate via wifi, on a plane, and talk to my sister in Belgium or my other sister in Argentina for free. I can choose to use text, voice, or video, crystal clear, no hassle, no money, no setup.<p>However, the killer feature is seamlessly having conversation on my phone, then continuing on my phone, then continuing on my laptop... etc