I've had Windows 8 on a non touch work laptop for nearly 7 months now. It took a while to get used to things, but now I am, it just works like Win 7.
You pin all of your favorite apps to the start bar on the desktop and you just point and shoot. Its just change. The underlying OS is rocksolid, it boots and sleeps much faster than Win 7 and that was light years ahead of Win XP.
With the Touchscreen aspect, Michael's mum is 75 and never had a computer. She was doing well with our Ipad, so when Windows 8 arrived we bought her a 24" all in one Lenovo with a touchscreen. She lives in the Windows 8 Metro interface and it lets her do everything she needs to do. IE Email, Youtube (mainly Cat Videos), Card Games, Memory games, Printing photos etc. Watching her try and use the mouse is hilarious, but she types quite well on the keyboard. For an older person, being able to touch what they want, rather than trying to relate a mouse to the cursor moving seems to get rid of half the battle.
The reason for the security warning with Windows XP, is that IE8 also goes end of life. I'm working with a 12,000 seat client at the moment, who is 60% of the way through their Win XP to Win 7 Migration. They still use IE8 for compatibility reasons, but this week, IE8 will be restricted to Intranet sites only, and Chrome is being deployed for the Internet. I'm pretty sure that IE8 is the newest IE that runs on XP, so that is why the security software is pushing the upgrade to Chrome. A Lack of Patching for the OS is one thing, a lack of Patching for a web browser is more of a problem.
So my Windows 8 experience is positive all round. Its Rock solid as far as reliability goes and Metro if you need a basic interface is good at what it does.