I would have made a better title, but lets go with it because they both are pretty comparable.
(Windows 8.1 - Windows 8)+ Windows 7= Windows 10
Windows 10 is fast, no doubt. Windows 10 is advanced, no doubt. But, their are few thing which is useless and seems to be forced on their users. If youre spending cash on it, then you should feel like using it not to be owned by product itself.
CONS
Remember the good old Windows 7 which is personally and professionally yours. You have choices to opt - in and out for specific thing without interrupting any thing else. But once you disable updates in Windows 10, the store will never works.
And why they included the new Edge browser? What its use? Are you trying to compete with google chrome? Are you trying to make a better browser program than opera? Please explain someone.
Edge is not for anything, its useless. It hangs a lot and very glitchy for copy paste operation, printing page is too squeky, lags and glitches. One more thing its not for commercial programs like SAP and JSP made company programs. Does it handles ActiveX controls like Internet Explorer handles? I doubt.
I got drivers issues with it. I was not able to connect to WiFi using latest drivers so I need to downgrade.
My mic is not working with Windows, even though all configurations are done very well. Do my mic works? No I am not dumb.
Cortana? who needs it anyway? Why it does not available in India(change regional settings)? And why it needs location access? I need answers.
Groove music player is a curse.
I will go in more depth and hunt out any con and update accordingly.
PRO
Its app handling process for modern/store apps and windows software is same. Unlike Windows 8.1. I am not talking about just the min max button for you clarity. Now, every modern app behaves like the traditional software. Which is quite good.
Its fast. no more comment required.
Tablet mode - I have iball Windows tablet and yes I have upgraded to windows 10 on it. Yeah its heavy and all I left with around 1.5GB remaining space after upgrading to it. Anyway, it works better and the new tablet mode is visually good and too user friendly. Fonts are big enough to see clearly which was earlier an issue with Windows 8. 8" tablet for being more specific.
The new task view is something which is not required but actually cool.
When you snap and dock one opened window to any side of the screen youre are given the option to choose whether the other open app goes to other side or not. Which is practically a useful concept. Thanks for it.
Start Menu, good old start menu.
Windows now automatically save screenshot to drive once after login to it. Its a good option but I miss the windows 8 feature in which it save to pictures folder much. Anyway, a good attempt, now atleast I cant miss them.
Action center is a great concept, like an android notification and quick access bar.
I will hunt and write down more once I found anything cool.