I just bought a cheap usb lead from ebay which seems to be working fine so far. Have played over 100 hours on GTAV, completed the walking dead 2, Metal gear rising, Tomb Raider, Resident Evil remake and Resident Evil 5 and it hasn't disconnected once. Think it was less than £2 from ebay..
I think the cheaper leads are better as they tend to have a smaller, lighter connector that is less likely to work loose once plugged into the pad.
Hopefully the wireless isn't far off as I hate having to use a wire. Either that or the new steam pad, if it's any good.