Windows 10 v/s Windows 8.1. What's new?

Microsoft unveiled the next version of Windows at a developer event in San Francisco, catching everyone by surprise by leap-frogging Windows 9 and labelling it Windows 10.
With many enterprise and power users sticking with Windows 7, due to its familiarity and stability, will Windows 10 offer enough features to justify an upgrade? We take a look at what Microsoft is offering.
1 - Start Button strikes back
Probably the biggest complaint about Windows 8 was the decision to ditch the familiar Start Button. Microsoft was so focused on introducing the world to its Live Tiles interface, it assumed users wouldn’t mind a Desktop with reduced functionality. It was a critical error, which has been addressed.
We’ve known for a while the Start button would make a triumphant return but we’re still excited as it will be supercharged. The Start Menu will allow you to access apps, search for content as well as pin apps, contacts and websites into it.

2 -  Windows 10 interface will adapt via Continuum
Microsoft was so keen to push the “touch-first” mantra with Window 8, the experience on traditional machines where keyboards and mice were the primary form of input suffered. This was addressed to some extent with the 8.1 update and the problem could now be solved with Windows 10.
Continuum will allow the Windows 10 interface to adapt based on the hardware it is running in. 
If you're working with a 2-in-1 hybrid like the Surface, you'll be met with the standard desktop while the Type Cover keyboard is connected. However, when you detach the keyboard the OS will detect this and prompt you to switch over to tablet mode.
3 - Multiple desktops debut 
Borrowing from Apple’s OS X, Microsoft has finally introduced multiple desktops.
This is something power users have been craving as it will make it easier to work on different projects simultaneously. This will also be handy for employees as they can keep their personal and work environments separate.
4 - A unified app store
Developers will now be able to create one app that runs across all Windows devices from phones through to 85in touch displays. 
Microsoft said it’s also going to allow volume app purchases based on existing organisational identity and allow businesses to reclaim or re-use licenses.
Larger enterprises will be able to create their own customised app store for employees, with the ability to include selected public apps alongside in-house apps.
5 - Universal apps
One of the main problems with Live Tile apps was the fact they could not be controlled like regular programs. This all changes with Universal apps. They will be framed in the same windows as programs so they can be resized, moved, maximized, minimized and closed.
6 - Flexible security updates
Security and critical updates will continue to be pushed out on a monthly basis.
Consumers will get updates as soon as they are ready via Windows Update and now businesses will be able to ‘opt-in’ to a fast-paced cycle as well.
Microsoft will also allows businesses to lock-down mission critical apps and segment user groups to deliver updates in a more flexible way too.
7 - Improved multitasking
Windows 10 will introduce a quadrant layout allowing up to four apps to be snapped on the same screen. The OS will even make smart suggestions to fill available screen space.
You’ll be able to cycle through open apps using the familiar Alt + Tab shortcut, but there is also a Task View button on the taskbar. Pressing this will show all open apps, allow you to re-arrange them and switch between virtual desktops.
8 - No more typos in Command Prompt
Power users rejoice as copy and paste will be enabled in Windows 10’s Command Prompt.
9 - MDM built in
Admins will be able to manage devices through traditional methods like Active Directory and System Center.
Windows 10 will include extended built-in mobile device management (MDM) capabilities - making it easier to manage device from the cloud.