Found a great post over at Wiep.net for SEO on link value factors:

It’s a known fact that no two links are equally the same, in this research I attempted to see every two links as equals. While this obviously makes it impossible to create a 100% accurate piece of content, this - together with the dozens of interesting comments- results in a document that might be of value for everybody who’s somehow [i]nvolved in building links. The grain of salt that comes with this research is far being outweighed by the value of the present data.

Probably my strongest opinion that conflicts in this area is usually over the concept that “Age of Domain” matters. I personally liked Ralph Tegtmeier’s answer:

“Only indirectly in that aged domains may have developed more trust and authority which tends to upgrade their outlinks’[s] impact.”

Still, as no real public econometric analysis has been done (that I know of or can find) most of the influence is still circumstantial and based on what people believe or non-statistically tested.