We too are stating facts, where is the killer function/feature that makes it worth our while and money to upgrade, currently I find very little reason.
This system is almost 5 years old but it does everything that I need of it and meets my requirements. As and when I decide to replace it, I will decide on what OS I will purchase then based on my requirements/needs. Having just added more RAM, changed to a silent/passive graphics card and just replaced my monitor, I don't think that will be any time soon.