Help me understand before I buy.... topic

Considering this watch to pair with my N4. With it having it's own dataplan/number, are there instances where I call and text someone from a number they aren't familiar with or does it forward everything through my phone? For instance, if I send a text from watch, does it come from watch # or my phone #? I've read that if it disconnects from your phone in standalone mode the phone will forward calls to it, but if I start a call from the watch...am I calling from the watch # or does it send the call to my cell that actually makes the call?
Also, what has been your monthly cost to your bill with this watch?

Thanks!