We used a gentle leader on our Dane/Lab mix. He had a long nose like a Dane, so it worked for him. I hate to see dogs with those fit poorly, rubbing on their eyes.
It worked really well on curbing his enthusiasm... he would get SOOOO excited on walks, that he would stop listening. The head-harness put a damper on his excitement, which worked at helping him 'listen' to the handler (mostly it was his dog-walker that needed to use it).
I'd opt for a prong first, personally... but... in Denna's case, she SHUT DOWN when I put a prong on her the first time - not even putting any pressure on it. I have no idea what was going through her mind, but as soon as I took it off, she JUMPED up off the pavement and was ready to walk again. Silly girl.
We use a nylon slip collar, like they use in the show ring. She does behave better with it on than her flat collar, even though I rarely need to put pressure on it... I do a LOT of talking when we're out walking, and she responds very well to verbal ques. She's very careful not to hit the end of the leash, because if she hits it too hard (which isn't very hard), I stop and/or start backing up, and she has to "come around" and get in a proper heel before we'll continue forward again. When doing that consistenty it didn't take long for her to figure out a work around, which was exactly what I wanted (i.e. stop hitting the end of the leash).
Denna was also a very social puppy who wanted to meet EVERYBODY out on the street. We got in the habit of sitting and waiting for people to come up and either pet her or pass by without interaction. That as a habit is very useful. She finally learned that it's OK when people don't pet her... she still gets a treat for sitting patiently as they pass by.