I've been running Microsoft Windows 10 for a few months now and my final opinion is "Nicely Done, Microsoft."
Bottom Line: If you are running a system with 4 GB of RAM or more, upgrading from Windows 7, 8 or 8.1 is a no-brainer. Absolutely "yes." Do it. Microsoft is offering a free upgrade and I would take it. The operating system is more functional than Windows 7 and considerably more esthetically pleasing than the 8 series of OS.
For images of the desktop, just use your favorite search engine and look for Windows 10 and select images.
Win 7 Users: You are in for a slight learning curve, not as bad as going from 7 to 8, but there is one.
Win 8 series Users: You're learning curve is actually down. I find Win 10 to be considerably more intuitive than the Win 8 series.
The bad: The only thing I have had trouble with is the VPN and Java-based executables. My corporation uses a Cisco VPN and their components do not run on Windows 8 nor do they run on the latest versions of Apple's iOS. This is a Cisco problem, not an Apple or Microsoft problem. I'm waiting for the company to get their heads back on straight. My fix is to run a virtual machine of 7 for when I need to VPN to work.
The good: Stability. Beauty, Intuitiveness. Those of you that are familiar with *nix's Cinnamon or XFC4 desktops will be comfortable.
In the end, It will be up to you to decide whether to upgrade or not, and you will have to live with it. Those of you that are upgrade haters, realize this: Software and Operating Systems have a limited lifetime of support. After their end of life (that is end of support) if you continue to run them, you may as well not use any security at all. Windows 7 and up are good for several years, but I still see people running XP. Upgrading and Updating is inevitable. Not to do so is personal security suicide.
Thanks for reading,