That's subjective. Like root? Faster updates? Less bloat? Less cost? Personally these are reasons I'd go for the one plus (or pixel) over the Galaxy.
Like tons of features? Probably louder headphone volume? A beautiful design? (Probable tie) a probable more solid design? Then the Sammy may be for you.
My OP6 feels like it'd break if I hold it wrong, just seems a bit fragile. My Galaxy S7 edge (I know it's old but it's my main line) feels a bit more built. I've had a couple notes that took some abuse before I cracked the screen and it was still usable, aside from the lag typing but this was note 4 and prior.
Not sure if I helped