Again, I must say it's all about preferences.
Like Shartley said and so many people said it : all you need for ''accuracy'' is 8 to 10 inch. That does not mean longer barrels are less accurate. That just means that the first 8 inches will determine the path of the ball.
but then you have porting and/or riffling, and all that might require longer barrels for other things

but just get what you like
If you get what you like, that will be the barrel for you

I like shorter barrels because I want my marker to be compact.. but that is me

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