Turning iMessage off does not work as advertised. I have my iPhone 5S right here in my hand. I can turn off iMessage right now and uncheck all email addresses (essentially an iMessage exorcism) and a different iPhone with iMessage on (that I can see right now in front of my eyes) continues to send SMS as an iMessage and even says "delivered". Delivered my @$$.
Once I am able to rid iMessage from my phones I will never turn it on. My cell phone number belongs to ME not Apple. SMS is the most basic, and in times of emergencies, sometimes the most reliable of electronic communications. Don't eff it up.
Whether:
1. You put your sim in a non-apple phone (blasphemy to the cult members. What if it's an emergency phone for temporary use genius?) or
2. Choose to turn OFF iMessage on the iPhone you are holding in your hand, Apple should not break SMS. Period. Apple is causing people to miss SMS messges with iMessage.
No amount of apologetics will explain this away. It's a defective service that actually requires one to contact customer service to get YOUR NUMBER disassociated from it? What?
One more thing. Any solution that requires me to proactively contact every iPhone owner I know (seems like a lot) and ask them to do something on their phone for the privilege of sending me an SMS.... well, the rules on this forum prohibit me from accurately describing my thoughts on this matter.