So, everyone's missing the obvious question, precipitated by:
"So I was swapping Schaller's for Dunlop Dual Design. "
Are you mad?
Peter (who will spare all his customary rant about the wonders of Schallers & lack thereof of Dunlops tonight)
For me it comes down to a few factors:
1) I have more basses with Dunlops than with Schallers. I'd like to be able to swap straps freely between all my basses, so having a single type of locking mechanism makes the most sense.
2) The Dunlop Duals are shaped more like a normal strap button, so in a pinch these work better (for me) than the Schallers with a conventional strap.
3) I've had a Schaller strap lock come apart on me. Not just come unscrewed, but actually come apart - like a weld failing
However due to the fact that I can't repair the end pin properly, I'll be using Schallers for a while yet. I was strictly a Schaller user for many years, but the number of Dunlop-bearing basses has grown over the years. Really,
I don't want to start a "Coke vs Pepsi" argument - They're both great.