Just back from WDW and HHI and we used a wireless router for Xbox (used to purchase movies), Itouch and Iphone.
The 3G ran very slow and the slower it runs the more it drains the battery. At HHI they have wireless, but you need a code to access and I had to keep logging in to use the wireless at the resort. It got to the point, I gave up using it, because it was tedious.
We tried to hook up the router at HHI but could not get it to work.
The router worked great, ran fast and covered the patio so I was very pleased we had it at WDW.
HHI had awful 3G coverage and our first day we lost cable tv and wi fi for several hours due to an outage on the entire Island. So be prepared to be disconnected no matter what you use at HHI.