So you can tether with your phone, do you go USB or Bluetooth?
Go USB; the results speak for themselves…
iPhone 4 (AT&T) over bluetooth:
iPhone 4 (AT&T) using USB:
I also have a Blackberry 8330 (Sprint) that I use for work, so I tested the same theory…
Blackberry 8330 (Sprint) over bluetooth:
(dial-up modem, no user/pass, dialing #777)
Blackberry 8330 (Sprint) using USB/Sprint Smartview:
