paint will hold it's color longer - and likely stay put longer.
opaque stain will protect from UV nearly as well as paint but not crack, peel, trap water, etc...
semi-opaque/semi-transparent have good UV inhibitors, protect from moisture, etc..
transparent stain will provide protection from water, but not UV.
plus, stain can be sprayed on every 3-4 years rather than brushing on of paint.