Harnesses to prevent pulling

Question
We have a 5-month-old golden retriever puppy who has gotten stubborn and bad about walking.  She will either pull on the leash, or sit and refuses to continue to walk or come.  We have seen recommendations for a head collar or harness to help with control.  What do you recommend?

Answer
I firmly believe in the head collar.  The leading brands are Promise,  Haltie, and Gentle Leader.  They have a strap going around the dogs nose looking something like a muzzle.  They work by pulling the dogs head around.  No other way gives you such great control with so little force.

I see references to using a harness, but hardly see how they would work.  I don't know anybody doing serious dog training that uses one.  What I see are various training collars, the common slip collar, head collars, prong collars, and the fabric versions of them.  

If getting out in front and coaxing the puppy doesn't work, try dropping back behind it and running past it in baby steps while calling ''Go, go, go!'' in an excited voice.  Then once it starts to pull, pull it backwards.  Try to avoid needing to do it in crowded public places.