I believe the iphone 5 has the highest bandwidth. On wifi in my house i get 40-50 down and 30-40 up.
On att LTE i average 20-40 down and around 10-15 up.
When i tether my ipad when using the iphone5 as a extender the ipad works like it is hooked right up to my wifi. Tethered on LTE it feels like it is hooked to my wifi also.
Note: I have 2 iphone 5s a iphone 4s and 2ipad 2s........the iphone 5 is faster then the ipad 2 on wifi....drawback 4 inch screen.
2600k HT on@4705mhz 2x EVGA GTX770 4gb Classified cards running in SLI @1320 mhz core and 2003 mhz mem,mounted in CM HAF922.2xHTPC's 2xi3 2120 3.3ghz dual core,1xasus LP HD6570 1xHIS hd7750@1150core1325mem,55"PanyVT30