We have some of both. Our house was originally built with wood windows. Stupid move on my part, because the builder said he could put in vinyl for a little more. Our addition has vinyl, and I love them. We've had them 10 yrs, no discoloration whatsover. We live in Virginia, so lots of sun and humidity. The wood on the outside of the kids' dormer windows upstairs is rotting because it has less of an overhang than the rest of the house. Also, with a west-facing exposure, it tends to get lots of rain and wind beating on it.