I have iMessage turned on, but I don't have carrier data because I'm almost always on wifi. I used to have carrier data and this all worked perfectly. On wifi, I try to iMessage an iPad of someone who I know has their iMessage turned on, and the status bar loads almost to the very end and does not send and 5 minutes later I get the "Message Failed to Send" popup. When not on wifi, texts attempt to go through as iMessages, but obviously don't and I have to force it through as an actual Text Message. Then when I do actually get within wifi, the messages I sent as texts, send AGAIN as iMessages. It's infuriating I have an iPhone 5 with latest iOS.