It is more resource efficient than Windows 7/8. Works better on low end systems.
Not for me it doesn't. I have upgraded two of my computers to Windows 10, and in both cases it is perceptively slower. In the case of my test system - a real low-end computer - I have taken a substantial performance cut since upgrading. I had been using the starter edition of Windows 7, and I upgraded it to 10 to lose the artificial restriction to 2GB of RAM. Yay! Now I can access all 4GB. But, boo! Not only does it run slower, but my computer fan runs more often as the CPU seems to idle at a higher percentage. This was done on a fresh install too.
The other computer (my work system) was a more modern, faster system. While the performance drop is far less pronounced, it is still noticeable. I upgraded the rest of our office and quite a number of people have complained how slow it seems.
I simply cannot understand why people claim that it is more efficient than previous versions of Windows - especially when compared to Windows 7. The most obvious slowness comes from the new don't-call-me-Metro user interface elements. It simply takes longer to display the new UI like menus and dialogs than the traditional ones. For example, it takes half the time for me to launch my old shareware spreadsheet Spread32 than it does to launch the new-look Windows calculator. The windows pop up in the same time, but it takes an extra second or so to display the buttons on the calc. And I no longer launch the calculator with a keyboard shortcut because 1) it is hard to set up as the tile no longer has the ability to set the shortcut (I had to create my own shortcut to calc.exe to make it work), and 2) it takes an extra two seconds to the launch time on my system when using the shortcut compared to clicking on a tile. This means it takes nearly 5.5 seconds to launch the calculator app via a keyboard shortcut. It is faster on my work computer, but it shows that Windows 10 does not run better on low-end systems.
You might think that it's just my slow computer to blame, but it never had this problem when it ran Windows 7 using half the memory.