I think it's great. There are a few bugs that Microsoft has to work out, but when they do, Windows 10 will be the best Windows OS.
Persoanlly, Windows Edge is not the greatest thing. It's still slow, but an improvement from IE.
I love all the new icons and how the layout and style of everything is. It's really modern and looks great.
The search feature, which has Cortana, is simply amazing. You can search the store, your computer, and the web all at the same time. It also has the ability to do voice searches.
Coming with this upgrade, I felt a small speed improvement. I don't know if this will happen to everyone though. However, Win 10 is much more compact than Win 8.
The start menu is back, thank God. They also removed charm bar, which I always hated.
I love the multitasking. From there, you can add more desktops.
Overall, Windows 10 is a great upgrade/install. I feel Windows has taken a taken a path in the right direction. They fixed everything they got wrong in 8/8.1. I hope this ends the cycle of bad Window OS's