Which connection is fastest for Hotspot?

I'm using iOS7 on an iPhone 5S. When I enable the Hotspot, which connection is fastest out of the USB, Bluetooth and wifi?

I have two Macs connected to a TimeCapsule router. The Mac Mini is hard wired. The MBP is wireless. If the MBP is doing a large download over wifi and I want to use the iPhone's Internet connection for the Mac Mini, what is the best way? I can't use wifi right because that is already bogged down by the MBP's download.

Yesterday I had the above scenario play out. I chose bluetooth. But the Internet connection to the Mac Mini was way to slow to be useful.