The front attachment harnesses such as Premier easy walk or the Sensation harness are good for big dogs as the lead is attached at the front so they can't lean into them as much and when they pull the front attachments helps to turn them towards you. They are very good.

I use a harness, for the reasons I detailed in the thread in training/behaviour.

I would always choose to use a harness on any dog that tolerates them (unless a harness is not suited to that particular breed ie. possible shoulder damage etc) but I also make sure I take time to walk them on collars as well just in case- sometimes you don't have time to put a harness on or someone else takes the dog for you and doesn't know how to fit the harness so it's worth having them used to a collar as well.

I always walk Takara using a double ended lead so if she's being a nuisance on the lead, I've found I can attach one end to the big (decorative) hoop on the front of her harness and keep the other hook attached to the normal D ring on the back and it stops her pulling!

Not designed for that but very handy all the same!