I use the threaded QD's as I can remove the hose easier for flushing out the lines. I do have a few of the barbed ones, like on my keg washer system. So, keeping the barbed ones do have other uses in the brewery. With the flared ones you do have extra parts and extra costs but being able to remove them easier makes up for it. I keep a few hoses with the ends for transfer hoses like filling from one keg to another.
Just so it's clear, these are the flared fittings with the barbed ends to connect to your hose. "Black" is Beer, "Grey" is gas. If you get a QD on the wrong keg post, you'll have a difficult time getting it off, even with keg lube.
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