Is there a comparison of networks and costs for iOS 4.3's Personal Hotspot? Is there a comparison of networks and their cost for the new Personal Hotspot feature?

Also, how does the hotspot feature differ from internet tethering in previous iOS versions?
The hotspot feature is, in essence, very similar to the Internet Tethering feature. The differences are that a) there's no cable required and b) you can connect up to 3* wifi-capable devices, so you're not restricted to tethering only devices that have USB or Bluetooth.

*See the below comments for the correct answer.