Textie for the iPhone - From the creator of Tweetie

I'm just trying it out with my wife's iTouch to my Droid. So far there's about a 50% loss rate on texts sent from Textie and a few that never got received (maybe 10%). A small sample, obviously, and it is free. Still, not a great initial showing.

Hasn't this been done with WhatsApp for iPhone and BB? Or am I missing something here?