Yeah you just rattled off the features of Google Voice (plus a few other services that do the same things).
It is indeed quite nice. No jailbreaking, managed in the same place as your contacts, texts, etc. Visible online, all the other benefits of Google Voice which I won't extol in detail.
The caveat there is you also have the drawbacks of google voice, most notably that MMS messages get silently dropped so neither you nor the sender know that you never received them.
There are also the privacy implications of going through google, if you care about such things.
It is indeed quite nice. No jailbreaking, managed in the same place as your contacts, texts, etc. Visible online, all the other benefits of Google Voice which I won't extol in detail.