Paint will eventually bubble and peel due to moisture especially if you live in a climate that gets rain, snow ice, and cold. Paint just sits on top of the wood and will require more work to remove it when it's time to redo your deck. An oil based stain that soaks into the wood is better than paint and will last longer. An oil based stain just fades over time and loses it's water repelling abilities but it is much easier to redo than paint. A simple cleaning with a deck cleaner, hose or power washer, dry time and then stain again.
Joseph: here's an answer from the experts!
Stain the deck, or use mineral oil on the wood. There are clear coatings for wood decks as well, Thompson’s water seal or generic version are ones I’ve used. It may require sanding before you treat it.
I would stain the deck. I used paint on the wooden ramp to a shed, and all the paint has peeled off.