Do I want it?
That depends on you...
It took me quite some time to get used to win 8, that I have on a Surface tablet..My first encounter with it did not go well.
However, If you do not have the same issues that I have, I think taking the free upgrade is worth it..
Not sure why they are doing it free...My gut feeling is that they want everyone to adopt it. It would be better for them and the OS works across all devices..plus the new browser is suppose to be the best they have ever made...purportedly..