I think a thing to remember is that Apple will probably iterate on this, much like any other technology, and make it better with each release. At least, that is my hope. I sadly don't have enough friends with iPhones to notice… so I'm stuck keeping my unlimited text messaging for the time being.
Thing that sucks the most about it is that I can only use this service from my iPad. I SMS mostly from my browser when I'm at my computer. Sometimes my iPad when I'm away, otherwise my phone. I'd like to be able to communicate with more Apple users a bit more freely.
There have been rumors of iChat getting iMessage integration of some kind.
But I'd like it to be taken a step further. I'd really like to be able to have my phone in a charger a la a WebOS device and have text messages and iMessages go directly to my computer or iPad so that I could reply from there. The messages can go through the internet from those devices, or directly through the iPhone. I don't care which, so long as I have the ability to use my Mac and iPad without having to use my phone for every message.
The author seems to have missed the fact that iMessage only lets you send non-sms messages when the other contact is online (blue "send" button), otherwise it's sms only (green button).
They never said you'd be able to send free SMS from an internet connection, so that table is kind of obvious. In the end, the user doesn't have to care, it just works. The only case where you might lose a message is if the recipient disconnects right before you send it, and even then you'll know it wasn't delivered. FaceTime is in much worse waters.
Just tested here. It will do that, but after a few minutes without confirmation, it will resend the message as SMS. You can explicitly tell it to do that by holding over a message baloon.
