I suspect the newer domain would look more active, more current and therefore more likely to host content useful now/of contemporary interest.

I suspect ranking 'degrades' slightly over time - don't keep adding content and lose places in the SERP.

Having said that, it's pretty much hypothetical. A ten year old domain will have more links and more content, and I think _that_ is why old domains rank well. It usually takes time to develop a great quantity of useful, ranking content and links, hence the perception that "aged domains" are more valuable.

Anyone else have thoughts / different view on this?