the rumor is long term domain registrations are good for SEO, shows you aren't a spammer... I don't think anybody has a definitive answer on how true this is or how much of a difference it makes.

As with everything else in SEO it depends. If the 1-year old domain has got a ton of great, related links already pointing to it, go with that one. Same goes for the 5-year old domain. More and better link, use the old one.

If SEO metrics are equal. It usually makes sense to go with the older domain.

Note in ranking age of a domain is still consider. To out rank an old domain you need to build its reputation and link(fast and reliable).

Age is a factor but age doesn't guarantee anything.. none of the SE's "demand" links.. if you're looking to rank at the top you simply have to get backlinks because as the net stands today in all of the engines links factor heavily into the algorithms used to rank each site.. and not just links alone but the types of links that you have and how many as well.