I have a MBP 17" 2010 (usb 2.0) and a rMBP 15" 2012 (usb 3.0). Both do not have a lighting port. I plan to buy a new rMBP when it comes out next year. I have decided to buy an iPhone 6S Plus. Is charging using the usb port of these laptops OK? Is it advisable to buy a Lighting Dock? Does it provide faster charging than the lighting to usb adapter that comes with the phone?