We upgraded both WIN7 and Win8.1 machines here (two of each machines in all) and they look abit different when converted over to WIN10... Even the LOGIN is different between the two models. I was expecting the screens to all look the same after they went to WIN10. I have the WIN8.1 Laptop machine and the wife has the WIN7 machine and my daughter has her WIN7 and WIN8 laptop machines. We have three DELL models and one HP model laptops here...
Ours all went without a hitch... We had to force the download of the last WIN7 machine which was taking forever to get the GO AHEAD from MS. After doing that it went without a hitch converting over.
I didn't like the new MS EDGE BROWSER and after trying to convert all of my apps over to that I finally went back to FIREFOX and GOOGLE CHROME... I use dual 24-inch monitors here with my DELL LAPTOP setup... Just couldn't get used to the small differences that EDGE was doing. It was a tad faster however...
The part I really like with WIN 10 is when you first turn it ON and log-in it almost jumps to the main view desktop scenes... Our WIN7 and WIN8 OSs would take several minutes sometimes to get to that point...
Roy Ken