armondhammer - 8:40 pm on Aug 28, 2012 (gmt 0)
Two cases are possible.
New site. Put up content, build links, and watch rankings grow slowly. Fight the newness of the domain, with the possible advantage of a more relevant, modern name. Still have to hustle and work the domain.
Use "old" site with new content. Watch rankings fluctuate as new site structure gets understood. Don't freak if things go down and stay the course. Settle in at some natural point in the future. Still have to hustle and work the domain.
The tradeoff, to me, is between the value of an aged domain as a trust factor, versus a potentially relevant fresh domain. Trust factors are gaining importance, but I doubt it trumps relevance. A secondary consideration would be the link structure of the old domain. Weak or strong could have still evolved without any "campaigns"
That said, it would appear that the old domain does already have some relevance. I'd factor that in. The big key is sticking to the plan even if rankings slip for a short time. I've rarely seen a major change to a site not result in a temporary loss of rank, especially recently.