If you are still considering whether or not you should upgrade to Windows 10, my advice would be wait. As with any new operating system there are bugs that need to be worked out. Some reports say that Windows 10 is the buggiest release so far. I can't confirm or deny these reports.
I would definitely recommend holding off if you are on a slow or metered internet service. The massive amount of updates to Windows 10 will slow your internet service way down. Microsoft has also taken the liberty of using your computer as part of a peer to peer network sharing service so they can push this new release out to other users. If you have already upgraded, call me and I will tell you how to shut down the share.
Have I seen anything good in Windows 10? The answer to that is yes. I think for those who truly hate the way Windows 8 looks you will appreciate that Windows 10 has done away with the charms bar and returned the more traditional looking start button menu. I'm also looking forward to seeing how well the phone companion app works. This may simplify the process of syncing iPhones and Android phones to a Windows computer. Although the Edge browser may not work on all websites yet it is definitely faster than Internet Explorer.
Would I tell you not to upgrade to Windows 10. The answer to that is no. It is, as always, your decision what you do with your computer. I just want everyone to realize there are hurdles and potential dangers. If you decide to do it and run into problems, you can always call me.