What are the equivalence of the marketed features of Windows Vista and OS X Tiger? What major features does Ubuntu (Feisty Fawn) have that Vista and Tiger does not?

Idea
Comparing the most marketed features of the latest operating systems from the major Operating system vendors: Microsoft, Apple and (for the sake of comparison) Canonical/Ubuntu Community (which leaves us with Vista, OS X Tiger and Feisty Fawn), could help get a rational overview of where the Desktop market is at present day and help make strategical decisions for those who are aiming to increase the share of Linux-based desktop computers through marketing efforts. Zealotry does not belong on this page, as does not irony or facts based on biased personal opinion. Keep it real and based upon the opinions of the majority of Desktop and Office user's, cited as needed.

https://wiki.ubuntu.com/ComparisonOfUbuntuOSXAndWindows

I have set up a wiki page skeleton above for this, but do not know enough to start filling in the facts. Please help building this resource if you believe in the idea! If you post your opinions here I will fill them in to the wiki page if they are found viable, intelligent and/or objective.

Thanks to and from all of the community!