Best actual, USB iPhone app?

I don't trust the Internet to download large files when transferring files via iCloud or whatever. So, I bought a 4 way 64 go usb. It works just great and all, I just can't get to work an iPhone because the apps I'm using suck. Anyone know a really good USB to iPhone app?

No sure what you don't trust? How is downloading to a USB any different than downloading directly to your phone. The only part that is different is the file going over wi-fi in your house (assuming you are on it). Yes, if you are transferring large files over cellular data that can take a lot longer.