Jofm5,
The hardware i.e processors is much quicker on the new iPhone although they haven't yet released the exact processor and memory speeds as of yet.
Just to add on the tethering WiFi, in the past your phones serial number would be the only device that could be used on the Cloud/BT network. From the update, you are going to be able to use two devices on the cloud network only, meaning BT won't work while tethering the device.