[jyl]

Ok.

Tethered to MacBook using Bluetooth. MacBook's WiFi turned off. iPhone WiFi turned off, connected via 3G. Speedtest.net run on Macbook's browser gives 790kb/s down.

iPhone WiFi turned on, connected via our home WiFi network. MacBook still tethered via Bluetooth. Speedtest.net on MacBook browser gets 1.1Mb/s down.

Switched MacBook's wifi back on, so MacBook connecting directly to home WiFi network, 11G. 7.6Mb/s down.

iMac cabled to the cable modem, 22.2Mb/s down. Comcast is doing well by me. I think they've rolled out DOCSIS 3.0 here.

For some reason I can't get tethering over USB to work. Also, one app (Radio France internet radio app) won't launch now - but haven't tried to launch it since upgrading to 3.0 anyway. Otherwise, all seems fine.

Thank you Mr Wizard!