I went flint for my first fun shooting front stuffer just to get as far back in time and as far away as I could from any cartridge gun association. I'm glad I did. The big PHOOF! going off inches in front of your nose is a FANTASTIC experience.
I've since gotten a percussion gun to go with the two flinters I've gotten just for the really wet and soggy days on the local club black powder trails. It's surprising how long and well a flinter CAN shoot in the rain. But eventually they get wet to where you need a good dozen tries to get them to fire. And that's where I drew the line.
There are a bunch of tricks to wet weather flint shooting. I'm learning them from the others that do well in the rain. But I'm not up to their level yet and generally find that I can't finish the whole 25 shot string once we're out from under the tree cover and on the last area where we're more exposed.
But on dry days? Flint all the way!
I drew the line between the choice of rifled vs smoothbore. I went rifled as at least a minimal nod to modernism. I've got enough problems hitting targets without watching the ball run out in a spiral path....

Having said that I've walked and shot the local trail with others that shoot smoothbore. And it's surprising what you can do with one once you get to know the right patch thickness, best lube and optimum charge to use. A good well tested and practiced smooth bore shooter can easily match a mediocre rifled barrel shooter.