Preparing win10 for installation - hints, tips + tricks?

Dear all,
does anybody have any experiences with windows 10 for installations? How to avoid upcoming popup, get a clean system, and so on?

Right now I don’t have a win10 system yet, but I need to get a new pc for performances. Either I’ll go for win 7 again or dive straight into win 10. What do you think?

Any recommendations welcome!

Thank you all!