I think the main reason people are upgrading is because Microsoft will end support for Windows 7 in 2020. I personally love Windows 7 and will probably not upgrade until security updates are discontinued.
The reason I still prefer Windows 7 over others is because it is very stable and easy to use. When Windows 8 came, I tried it but encountered many problems so I changed it back to 7.
Windows 7 is much better for me, because it is easy to use, to navigate the tools. the system most of the time support most application or software, it consume little bit capacity in hard drive. in terms of games whether offline or online most of the time windows 7 has a compatibility with in some installer. unlike windows 10, in my own view, it was release and design with the latest PC's mostly, touch screen Computer. in terms of the software, I think windows 10 has a limited capability and compatibility.
Windows 7 is incomparable with Windows 10 because its honestly perfect. It barely crashes, i can run both old and new games without any compatibility problems but sometimes error occurs. Mainly, no forced updates, no bloatware and you have the good old classic start menu, transparent window and taskbar, windows media center and 3d aero flip
I would say better, as it is hard to find something that would be better on 7 than on 10. So here's the list:
1. Boots much faster
2. Syncs data - if you log in with a Microsoft account, your Windows settings will be synced. Also there is Onedrive available out of box if you want to sync your files.
3. Has a good browser out of box - Edge performs as good as other top browsers (though it still might get confused if you have huge number of tabs opened for a long time), and unlike Internet explorer. It is also sandboxed by system so potentially offering better security. Of course you can still use whatever you've got used, just you gain one new worthy option.
4. Windows Store - every Windows 7 app has a potential to do a malicious thing to the system, and nearly every of them at least somewhat slows down the system. All that things goes away with Windows Store. Unfortunately, right now there is more crap there than useful things, but still there is a decent choice of useful apps, and I guess that even if you find just one app that you will use it's still a great addon to your Windows experience.
5. Virtual desktops
6. Mail and Calendar available out of box (though fairly basic).
I have PCs with Win7 and Linux.
But earlier, I used windows7 for some Windows specific VPN client softwares, through which only I was allowed to gain access few server infrastructure for administration.
Rarely touch Windows now, always comfortable with Linux.