I honestly find Windows 10 privacy settings more reachable and easily to understand than Windows 8/8.1. I also pretty like background apps loading settings. They also improved the installation setup for choosing the local account, while in Windows 8.1 is quite an hidden option. Moreover I do not have to run exotic commands any-more to update default Windows Store applications without a MS account.
What I don't like is the lack of a TV-Tuner player + DVR (WMC) and the lack of a better control of Windows Update (forcing security settings is good, but I am not so sure about drivers and OS update components) and the need to edit group policy settings (gpedit.msc) or the registry (Windows 10 home) to disable Defender.
Things I didn't like at Windows 10
- Start Menu is a big joke, its Start Screen scaled down. I'd prefer Win 8.1 style Start Screen (which Win 10 doesn't provide afaik)
- Automatic Updates (yes you can disable or prevent automatic install but there is no way to install selected updates
- Windows Defender (you can disable again though, http://www.tenforums.com/tutorials/5918-windows-defender-turn-off-windows-10-a.html )
- No active window color (I had never seen such annoying UI/UX decision from Microsoft before, simply can't get which window is active easily, also border width (1 px apparently) is annoying as well. Win 8.1 style is just fine)
- Edge is a bad implemented good idea, found "homepage" annoying.
- I have privacy concerns (due to telemetry service and new privacy policy)
- It may be me but seemed slower than Win 8.1
- Notification Center can't be disabled fully, system messages still come.
Things I liked at Windows 10
- Making apps windowed, takes less place and usable (It was weird to use Calculator app fullscreen on Full HD monitor)
- New notification area icons.
- Tbh, I believe thats all, I am not interested in DX12 :)