It flat out works great.
Its now possible to send messages to iPhone users, and they will always get the notification, regardless of what apps they have open, or if the phone is in standby. Previously the only two things that would always notify the phone were actual phone calls and SMS messages.
This is the beginning of the end for SMS. The most over-priced 'feature' of phones is finally being attacked. Not by laws, not by outrage, but by innovation.