I have an ATT iPhone 4S and recently began using the mobile hotspot feature for work. I am connecting an iPad 4 via bluetooth and my macbook air via bluetooth or USB. I found that the MBA speeds were significantly slower than while using the iPad. Even so, the iPad tethered to the 4S isn't exactly "fast". I know there are other variables involved, but in general how much better would an iPhone 5 be with mobile hotspot/tethering speeds?