I installed it yesterday on a laptop that I bought on Day 1 of the Win 7 release, so its about 6 years old now. My first impressions are pretty good, actually. Boot/shut down times are much improved. It has a lot of configuration options to tweak. Solitaire is back! (But you'll have to find it!)
The biggest downside so far is the way that it takes control of your BIOS/UEFI boot options. Uh, you have no boot options anymore! This began with Win 8, but Win 8 required UEFI systems. My 6-yr old laptop is totally legacy BIOS, not UEFI, but Win 10 has still locked it up so that there is no option to enter "Setup" or change "Boot order" except by jumping through specific M$ hoops before rebooting. Here are the hoops to jump:
Settings -> Update and Recovery -> Recovery -> Advanced Startup/Restart Now
and then
Option/Troubleshoot -> Advanced Options -> Startup Repair
Then it will finally reboot. Be quick to hit F1, F2, Del, or whatever you need to use! When you're finally finished and go back to Win 10, you will have to navigate the "Startup Repair" app that you told it you wanted to use. Of course, there is nothing to repair, but it will be a further delay to getting back to a normal operating state.
So, you think you want to go through this every time you want to try out the latest distro on a live DVD? It may be time to get a little more familiar with VirtualBox!
Cheers!