Hello, it depends a bit on what kind of feel you want for the ceiling. With a plank ceiling, you get more character. MDF is also an okay solution if you have time to paint it with a brush to give it more character; if you use a roller or spray gun, it tends to look rather flat.
One solution to avoid potential shrinkage with a real wooden ceiling is to prime the planks before installation; that way, if there is any shrinkage, it will still look white.
I would go with a real wooden ceiling for a more solid feel; you can sort out the bad pieces. Just make sure to start straight when putting it up to avoid skewing, as you have quite a large area
