One our 2 desktops that get used daily I upgraded from W7 to W8. Things are sometimes on different places and in some cases you just need to do things differently. Yes, this can mean extra mouse clicks. The Live Tiles (which can be active and use the Internet, thus drain battery power, but can be turned off) offer little to a PC user but for the Surface RT, make it act like a tablet such as the iPad. Most, if not all, the Live Tiles are like iPad apps.
One can by-pass the Start Screen and restore the Start Orb using one of many 3rd party alternatives.
My wife's machine was 'our' test of this. I figured she'd complain about anything, so I'd try it out on her desktop. Well, other than one extra click to go from the Start Screen to the Desktop, she's very happy. Admittedly she doesn't use a lot of features and doesn't need to find and play with the Control panel, but overall it works just fine.
I should add she did have problems with existing programs that either needed to be re-installed or just didn't work. The W8 Advisor does detail most of these, and some are wrong, stating they do work when they do not. Norton Ghost 15 is one of these.
One big PRO, It will be supported longer than W7 will be. It also appears faster, but that is subjective.
CON would be non-supported programs and locating 'things' that have been moved.
Touch screen is NOT needed. There are mice and pads on can buy though that will work as one, but you can navigate just as well with a mouse. You just have to learn to do things differently.
Live Tiles for instance just like on any tablet stay loaded and might even be running. If you use ALT-F4, you will close them, they have NO close button. As I said, they also will update the Start Screen, and you can disable this to reduce Internet load.